Journal articles on the topic 'Wall suction'
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Zhao, Jianghong, Xin Li, and Jin Bai. "Experimental study of vortex suction unit-based wall-climbing robot on walls with various surface conditions." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 232, no. 21 (August 17, 2018): 3977–91. http://dx.doi.org/10.1177/0954406218791203.
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This study presents a wall-climbing robot called Vortexbot. Vortexbot has a suction unit that uses vortex flow to generate a suction force. Unlike the traditional unit based on contact-type suction, the suction unit can maintain a suction force without any contact with the wall surface. Therefore, the suction unit can provide a climbing robot with sufficient stable suction force even on walls with very rough surfaces and raised obstacles/grooves, and there is no wear and tear. Furthermore, the compressed air vents from the gap between the suction unit and the wall surface after rotating in the vortex chamber. Hence, such kind of flow direction can avoid the effect of the dust and dropped items on the wall surface. In this paper, we first introduced the vortex suction unit principle and discuss the feasibility of its application to a wall-climbing robot. Subsequently, the mechanical structure of Vortexbot was designed. After which, we surveyed the suction properties of the suction unit on a smooth wall surface. Then the functional relationship between the percentage change in the suction force and the supply flow rate was obtained. In addition, we studied the effect of the roughness and shape (a raised obstacle and groove) of the wall surface on the suction performance of the suction unit. Finally, we experimentally verified the climbing performance of Vortexbot on several kinds of walls with different surface conditions. It was confirmed that using the suction unit improves the robot’s climbing performance.
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Abu-Nada, E., A. Al-Sarkhi, B. Akash, and I. Al-Hinti. "Heat Transfer and Fluid Flow Characteristics of Separated Flows Encountered in a Backward-Facing Step Under the Effect of Suction and Blowing." Journal of Heat Transfer 129, no. 11 (February 1, 2007): 1517–28. http://dx.doi.org/10.1115/1.2759973.
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Abstract Numerical investigation of heat transfer and fluid flow over a backward-facing step (BFS), under the effect of suction and blowing, is presented. Here, suction/blowing is implemented on the bottom wall (adjacent to the step). The finite volume technique is used. The distribution of the modified coefficient of friction and Nusselt number at the top and bottom walls of the BFS are obtained. On the bottom wall, and inside the primary recirculation bubble, suction increases the modified coefficient of friction and blowing reduces it. However, after the point of reattachment, mass augmentation causes an increase in the modified coefficient of friction and mass reduction causes a decrease in modified coefficient of friction. On the top wall, suction decreases the modified coefficient of friction and blowing increases it. Local Nusselt number on the bottom wall is increased by suction and is decreased by blowing, and the contrary occurs on the top wall. The maximum local Nusselt number on the bottom wall coincides with the point of reattachment. High values of average Nusselt number on the bottom wall are identified at high Reynolds numbers and high suction bleed rates. However, the low values correspond to high blowing rates. The reattachment length and the length of the top secondary recirculation bubble are computed under the effect of suction and blowing. The reattachment length is increased by increasing blowing bleed rate and is decreased by increasing suction bleed rate. The spots of high Nusselt number, and low coefficient of friction, are identified by using contour maps.
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Michinaga, Yuki, Tamaki Takano, Takamitsu Terasaki, Souma Miyazaki, Noritoshi Kikuchi, and Kenji Okada. "Hemolytic characteristics of three suctioning systems for use with a newly developed cardiopulmonary bypass system." Perfusion 34, no. 2 (August 19, 2018): 136–42. http://dx.doi.org/10.1177/0267659118793559.
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Introduction: We have been developing a closed-circuit cardiopulmonary bypass (CPB) system (“Dihead CPB”) for application during coronary artery bypass grafting (CABG) and valve surgery. To strive for minimal hemolysis during Dihead CPB, we compared the hemolysis caused by three different suction systems and performed a clinical study with the newly applied suction system. Materials & Methods: We evaluated the hemolysis caused by roller-pump suction, the SmartSuction® Harmony® and wall suction systems with respect to suction speed and compared the systems by means of in vitro studies. A clinical study was also performed on 15 volunteers to assess hemolysis and the adequacy of the newly applied suction system with Dihead CPB. Results: Pressure inside the suction cannula was −22.5 ± 0.1 mmHg at a maximum flow of 1.5 L/min for roller-pump suction and −43.4 ± 0.1 mmHg at −150 mmHg of the set vacuum pressure of wall suction. With the SmartSuction, the pressure inside the cannula varied from −76.3 ± 1.0 to −130.3 ± 1.5 mmHg, depending on suctioning conditions. Suction speed (to suction 50 ml of blood) was fastest with the SmartSuction (69.7 ± 3.58 s) whereas, with roller suction, it was 117.3 ± 8.47 s and with wall suction 96.9 ± 7.10 s. The SmartSuction had the highest hemolysis rate (2.00 ± 0.33%) vs. 0.61 ± 0.10% for roller suction and 0.41 ± 0.11% for wall suction (p<0.001). The clinical study with wall suction showed no significant increase in plasma free hemoglobin during or after CPB compared with before surgery. Conclusions: Wall suction had less hemolysis than roller suction or the SmartSuction in the in vitro study and the clinical study with wall suction showed efficient suction speed and acceptable hemolysis, suggesting that Dihead CPB with wall suction is feasible for CABG.
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Gofar, Nurly, and Hanafiah. "Contribution of suction on the stability of reinforced-soil retaining wall." MATEC Web of Conferences 195 (2018): 03004. http://dx.doi.org/10.1051/matecconf/201819503004.
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Existing design methods of a reinforced-soil retaining wall were established for walls with cohesionless soil backfill. However, local soil has been used widely in the construction of such a wall for economic reasons. Laboratory and numerical studies have pointed out the merit of using cohesive backfill in association with geosynthetic reinforcement. Since the compacted soil was in an unsaturated condition during the construction of the reinforced wall, the apparent cohesion derived from both soil mineralogy and suction could contribute to the stability of the wall. This paper considers methods to include the suction contribution to the existing design guidelines based on slope stability analysis, i.e. simplified method and simplified stiffness method. The analyses were carried out on a case study of geosynthetics reinforced soil retaining wall. Results show that the contribution of suction as part of cohesion existing in the cohesive backfill could be considered for the stability analysis of reinforced soil retaining walls using the available design guidelines.
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Muthuraj, R., and S. Srinivas. "Influence of magnetic field and wall slip conditions on steady flow between parallel flat wall and a long wavy wall with Soret effect." Journal of Naval Architecture and Marine Engineering 6, no. 2 (June 23, 2010): 62–71. http://dx.doi.org/10.3329/jname.v6i2.3061.
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The steady MHD flow in the presence of temperature dependent heat source in a viscous incompressible fluid bounded by a parallel flat wall and a long wavy wall is studied with heat and mass transfer, taking into account the thermal-diffusion (Soret) effects, when the no-slip condition at the channel wall in no longer valid. An external uniform magnetic field and a uniform suction are applied perpendicular to the flat wall. The walls are kept at different but constant temperatures. The velocity, temperature and concentration field have been evaluated numerically for various values of the parameters entering the problem. The skin friction, rate of heat and mass transfer at the walls are obtained and discussed graphically. Keywords: Wavy wall; slip parameter; Sherwood number; suction parameter; Soret number DOI: 10.3329/jname.v6i2.3061
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Tokuomi, Saeko, and Kazuya Mori. "Suction Cup for Concrete Wall Testing Robot." Journal of Robotics and Mechatronics 28, no. 2 (April 19, 2016): 194–97. http://dx.doi.org/10.20965/jrm.2016.p0194.
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[abstFig src='/00280002/10.jpg' width=""300"" text='Claws attached to suction cups' ]Efficient economical test methods are widely needed worldwide. One target of this is to develop climbing robots that check for defects in concrete. These concrete-wall-climbing robots generally use suction cups to support themselves and test apparatus, but the danger exists of this expensive equipment falling. This may occur due to one of two reasons. The first is inadequate ring-seal decompression in suction cups and the second is suction cup slippage. We have added claws to suction cups to help prevent slippage. The claws we developed are attached to the suction cups to help grip the wall. In the sections below, we discuss the scratch tests we performed to test claw effectiveness in improving suction cup grip. We then prove through tests under actual conditions that the estimated grip force matched that of an actual suction cup's grip force with the claw.
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DEY, SUBHASISH, TUSHAR K. NATH, and SUJIT K. BOSE. "Submerged wall jets subjected to injection and suction from the wall." Journal of Fluid Mechanics 653 (April 27, 2010): 57–97. http://dx.doi.org/10.1017/s0022112010000182.
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This paper presents an experimental study on turbulent flow characteristics in submerged plane wall jets subjected to injection (upward seepage) and suction (downward seepage) from the wall. The vertical distributions of time-averaged velocity components, turbulence intensity components and Reynolds shear stress at different horizontal distances are presented. The horizontal distributions of wall shear stress determined from the Reynolds shear stress profiles are also furnished. The flow field exhibits a decay of the jet velocity over a horizontal distance. The wall shear stress and the rate of decay of the jet velocity increase in the presence of injection and decrease with suction. Based on the two-dimensional Reynolds-averaged Navier–Stokes equations of a steady turbulent flow, the velocity and Reynolds shear stress distributions in the fully developed zone subjected to no seepage, injection and suction are theoretically computed. The response of the turbulent flow characteristics to injection and suction is analysed from the point of view of similarity characteristics, growth of the length scale and decay of the velocity and turbulence characteristics scales. The significant observation is that the velocity, Reynolds shear stress and turbulence intensities in the fully developed zone are reasonably similar under both injection and suction on applying the appropriate scaling laws. An analysis of the third-order moments of velocity fluctuations reveals that the inner layer of the jet is associated with the arrival of low-speed fluid streaks causing an effect of retardation. On the other hand, the upper layer of the jet is associated with the arrival of high-speed fluid streaks causing an effect of acceleration. Injection influences the near-wall distributions of the third-order moments by increasing the upward turbulent advection of the streamwise Reynolds normal stress. In contrast, suction influences the near-wall distributions of the third-order moments by increasing the downward turbulent advection of the streamwise Reynolds normal stress. Also, injection and suction change the vertical turbulent flux of the vertical Reynolds normal stress in a similar way. The streamwise turbulent energy flux travels towards the jet origin within the jet layer, while it travels away from the origin within the inner layer of the circulatory flow. The turbulent energy budget suggests that the turbulent and pressure energy diffusions oppose each other, and the turbulent dissipation lags the turbulent production. The quadrant analysis of velocity fluctuations reveals that the inward and outward interactions are the primary contributions to the Reynolds shear stress production in the inner and outer layers of the jet, respectively. However, injection induces feeble ejections in the vicinity of the wall.
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Portelinha, Fernando H. M., Jorge G. Zornberg, and Orencio M. Vilar. "Deformation analysis of an unsaturated geosynthetic reinforced soil wall subjected to infiltration." MATEC Web of Conferences 337 (2021): 03018. http://dx.doi.org/10.1051/matecconf/202133703018.
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Geosynthetic-reinforced soil walls are structures typically constructed with compacted and thus unsaturated soils. The use of local fine-grained soils as backfill material has been a common practice in view of the significant cost reduction in comparison to granular backfills. This is especially applicable in tropical areas where lateritic soils are found as these material scan exhibit outstanding geotechnical properties mainly under unsaturated conditions. Thus, it is possible to optimize the design and construction of geosynthetic-reinforced soil walls considering soil unsaturation, however it is not known to what extent infiltration can reduce soil suction impairing the safety of the structure. To address the influence of suction on the behavior of geosynthetic structures, a full-scale geotextile-reinforced wall was subjected to infiltration and instrumented to capture the distribution of moisture and soil suction along the reinforced zone, as well as reinforcements strains. This paper presents and discuss the influence of geotextile reinforcement acting as capillary barrier coupled with the wall performance. Results demonstrate that the advancement of infiltration front has a more pronounced effect on deformation as the changes on water contents. Capillary barriers were found to occur retarding infiltration, but not affecting the overall performance of the structure. The average of monitored suction values along the wall height, herein called as “global suction”, was found to be strictly related to maximum reinforcement strains behavior.
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Ricco, Pierre, Daniel Shah, and Peter D. Hicks. "Compressible laminar streaks with wall suction." Physics of Fluids 25, no. 5 (May 2013): 054110. http://dx.doi.org/10.1063/1.4807066.
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Chen, Rui, Leilei Fu, Yilin Qiu, Ruizhou Song, and Yan Jin. "A gecko-inspired wall-climbing robot based on vibration suction mechanism." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 19-20 (August 18, 2019): 7132–43. http://dx.doi.org/10.1177/0954406219869041.
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A prototype of gecko-inspired wall-climbing robot based on vibration suction mechanism is proposed. The robot adheres to the wall surface based on a novel negative pressure technology named as vibration suction. According to the theory of vibration suction, the vibration suction module is designed as the foot of the wall-climbing robot. In addition, the tripod gait of geckos is taken into account in the motion planning of the robot. By combining the unique properties of vibration suction mechanism and the tripod gait of the geckos, several advantages including stable motion, certain load capacity, anti-overturning ability, and good suction force to the wall surfaces are obtained. The climbing ability is verified by the experiment on the surface of the glass, which manifests that the robot can climb vertically at the highest speed of 13.75 mm/s with a spot turning at the single maximum turning angle of 20°. Potential applications of this proposed climbing robot in some fields include repair, construction, cleaning, and exploration.
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Lim, Byung Ju, Young Bog Ham, and Chang Dae Park. "Experiment for Attaching Force of a Suction Fan on Various Concrete Wall Surfaces." Applied Mechanics and Materials 166-169 (May 2012): 853–58. http://dx.doi.org/10.4028/www.scientific.net/amm.166-169.853.
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In order to measure attaching performance of the suction fan against a concrete wall, test apparatus measuring suction force of the fan was developed. Using this test apparatus, four types of concrete wall specimens were tested to measure the attaching force. The test apparatus consisted of a fan motor, a pneumatic cylinder, a load cell, and sensors for vacuum pressure and a rotating speed of the fan. Vertical wall surface of concrete material were manufactured to four different shapes that is flat, step, rib and embossing type. When the fan is rotating in the fan-housing which is fixed by metal frame, the wall specimen is moved near to fan-housing edge by the pneumatic cylinder. And the specimen may be attached to fan-housing edge by suction force of the fan, and the wall specimen is reversely moved away from the fan-housing edge by the pneumatic cylinder. Then suction force of the fan was measured using a load cell. And the suction force was measured depending on specimen types and varying the rotation speed of the fan. Test result shows that the fan speed is proportional to the suction force, and interestingly, suction force is almost independent from the specimen shapes. The maximum suction force was equally measured with 231.9 N on the step and embossing type surface with 1,800 rpm.
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FLORYAN, J. M. "Stability of wall-bounded shear layers in the presence of simulated distributed surface roughness." Journal of Fluid Mechanics 335 (March 25, 1997): 29–55. http://dx.doi.org/10.1017/s0022112096004429.
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Linear stability of wall-bounded shear layers modified by distributed suction has been considered. Wall suction was introduced in order to simulate distributed surface roughness. In all cases studied, i.e. Poiseuille and Couette flows and Blasius boundary layer, wall suction was able to induce a new type of instability characterized by the appearance of streamwise vortices. Results of calculations show that a linear model of suction-induced flow modifications provides a sufficiently accurate representation of the basic state. The effects of an arbitrary suction distribution can, therefore, be assessed by decomposing this distribution into Fourier series and carrying out stability analysis on a mode-by-mode basis, i.e. once and for ever.
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Doosti Abukheyli, A., H. Hassanzadeh, and SA Mirbozorgi. "Pseudo 3D modeling of suction and injection effects on fully developed laminar flow and heat transfer in rectangular fuel cell channels." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 232, no. 3 (September 20, 2017): 266–81. http://dx.doi.org/10.1177/0957650917732450.
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In this paper, the flow in the rectangular fuel cell channel with different aspect ratios has been numerically simulated. The bottom wall of the rectangular channel is porous and subjected to a uniform mass injection or suction, while the other three walls are nonporous or impermeable. Assuming the hydro-dynamically and thermally fully developed flow, the mass, momentum, and energy equations have been solved with a two-dimensional code. The present numerical results are in good agreement with the numerical results in the literature. The wall friction coefficients and Nusselt numbers were obtained for different aspect ratios, different wall Reynolds numbers (for suction and injection), and different thermal boundary conditions. The results show that for each aspect ratio, friction coefficient ( fRe) is larger for injection than for suction. Also at unit expect ratio, a/ b = 1, the fRe have minimum value for each wall Reynolds number ( Rem) and with increasing and decreasing aspect ratio, fRe increases. The changes of Nusselt ( Nu) number with Rem and aspect ratio is dependent on the thermal boundary conditions and definition of Nu number (for combined boundary condition).
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AMITAY, MICHAEL, and JACOB COHEN. "Instability of a two-dimensional plane wall jet subjected to blowing or suction." Journal of Fluid Mechanics 344 (August 10, 1997): 67–94. http://dx.doi.org/10.1017/s0022112097006071.
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The effects of wall blowing or suction on the stability characteristics of a laminar incompressible two-dimensional plane wall jet are investigated both experimentally and theoretically. A quantitative comparison between linear stability calculations and phase-locked experimental data, obtained when the wall jet is subjected to two-dimensional excitations, confirms the co-existence of the viscous and inviscid instability modes and the theoretically predicted effects of blowing and suction on the stability of the wall jet. According to these predicted effects, blowing stabilizes the inviscid mode while destabilizing the viscous one; suction has the opposite effect. Furthermore, blowing and suction tend to increase and decrease, respectively, the ratio between the outer and inner amplitude maxima of the streamwise velocity fluctuation. When wall blowing is applied, the instability domain is enlarged and includes higher-frequency waves. In addition, the region where both unstable modes co-exist simultaneously begins at a lower local Reynolds number. Opposite effects are caused when suction is applied. The quantitative comparison between the theory and experiment includes the cross-stream structure and the downstream growth of the streamwise velocity fluctuations. In order to accurately account for the effect of the mean flow divergence in the stability analysis, the second-order corrections to the mean flow solutions are obtained for all wall conditions. Spectral distributions, obtained when natural wall-jets are subjected to blowing and suction, support qualitatively the above results.
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ASAI, MASAHITO, YASUFUMI KONISHI, YUKI OIZUMI, and MICHIO NISHIOKA. "Growth and breakdown of low-speed streaks leading to wall turbulence." Journal of Fluid Mechanics 586 (August 14, 2007): 371–96. http://dx.doi.org/10.1017/s002211200700688x.
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Two-dimensional local wall suction is applied to a fully developed turbulent boundary layer such that near-wall turbulence structures are completely sucked out, but most of the turbulent vortices in the original outer layer can survive the suction and cause the resulting laminar flow to undergo re-transition. This enables us to observe and clarify the whole process by which the suction-surviving strong vortical motions give rise to near-wall low-speed streaks and eventually generate wall turbulence. Hot-wire and particle image velocimetry (PIV) measurements show that low-frequency velocity fluctuations, which are markedly suppressed near the wall by the local wall suction, soon start to grow downstream of the suction. The growth of low-frequency fluctuations is algebraic. This characterizes the streak growth caused by the suction-surviving turbulent vortices. The low-speed streaks obtain almost the same spanwise spacing as that of the original turbulent boundary layer without the suction even in the initial stage of the streak development. This indicates that the suction-surviving turbulent vortices are efficient in exciting the necessary ingredients for the wall turbulence, namely, low-speed streaks of the correct scale. After attaining near-saturation, the low-speed streaks soon undergo sinuous instability to lead to re-transition. Flow visualization shows that the streak instability and its subsequent breakdown occur at random in space and time in spite of the spanwise arrangement of streaks being almost periodic. Even under the high-intensity turbulence conditions, the sinuous instability amplifies disturbances of almost the same wavelength as predicted from the linear stability theory, though the actual growth is in the form of a wave packet with not more than two waves. It should be emphasized that the mean velocity develops the log-law profile as the streak breakdown proceeds. The transient growth and eventual breakdown of low-speed streaks are also discussed in connection with the critical condition for the wall-turbulence generation.
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Chang, Tong-Bou. "Theoretical Analysis of Effects of Wall Suction on Entropy Generation Rate in Laminar Condensate Layer on Horizontal Tube." Mathematical Problems in Engineering 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/172605.
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The effects of wall suction on the entropy generation rate in a two-dimensional steady film condensation flow on a horizontal tube are investigated theoretically. In analyzing the liquid flow, the effects of both the gravitational force and the viscous force are taken into account. In addition, a film thickness reduction ratio,Sf, is introduced to evaluate the effect of wall suction on the thickness of the condensate layer. The analytical results show that, the entropy generation rate depends on the Jakob number Ja, the Rayleigh number Ra, the Brinkman number Br, the dimensionless temperature differenceψ, and the wall suction parameterSw. In addition, it is shown that in the absence of wall suction, a closed-form correlation for the Nusselt number can be derived. Finally, it is shown that the dimensionless entropy generation due to heat transfer,NT, increases with an increasing suction parameterSw, whereas the dimensionless entropy generation due to liquid film flow friction,NF, decreases.
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Ho, Joanna, Thomas C. Corke, and Eric Matlis. "Effect of wall suction on rotating disk absolute instability." Journal of Fluid Mechanics 791 (February 24, 2016): 704–37. http://dx.doi.org/10.1017/jfm.2015.735.
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This research investigates the effect of uniform suction on the absolute instability of Type I cross-flow modes in the boundary layer on a rotating disk. Specifically, it is designed to investigate whether wall suction would transform the absolute instability into a global mode, as first postulated in the numerical simulations of Davies & Carpenter (J. Fluid Mech., vol. 486, 2003, pp. 287–329). The disk is designed so that with a suction parameter of $0.2$, the radial location of the absolute instability critical Reynolds number, $Re_{c_{A}}=650$, occurs on the disk. Wall suction is applied from $Re=317$ to 696.5. The design for wall suction follows that of Gregory & Walker (J. Fluid Mech., 1960, pp. 225–234) where an array of holes through the disk communicate between the measurement side of the disk and the underside of the disk which is inside of an enclosure that is maintained at a slight vacuum. The enclosure pressure is adjustable so that a range of suction or blowing parameters can be investigated. The holes in the measurement surface are covered by a compressed wire porous mesh to aid in uniformizing the suction on the measurement surface of the disk. The mesh is covered by a thin porous high-density polyethylene sheet featuring a $20~{\rm\mu}\text{m}$ pore size which provides a smooth finely porous surface. A companion numerical simulation is performed to investigate the effect that the size and vacuum pressure of the underside enclosure have on the uniformity of the measurement surface suction. Temporal disturbances are introduced using the method of Othman & Corke (J. Fluid Mech., 2006, pp. 63–94). The results document the evolution of disturbance wavepackets in space and time. These show a temporal growth of the wavepackets as the location of the absolute instability is approached which is in strong contrast to the temporal evolution without suction observed by Othman and Corke. The results appear to support the effect of wall suction on the absolute instability postulated by Thomas (PhD thesis, 2007, Cardiff University, UK) and Thomas & Davies (J. Fluid Mech., vol. 663, 2010, pp. 401–433).
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Sofialidis, D., and P. Prinos. "Wall Suction Effects on the Structure of Fully Developed Turbulent Pipe Flow." Journal of Fluids Engineering 118, no. 1 (March 1, 1996): 33–39. http://dx.doi.org/10.1115/1.2817507.
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The effects of wall suction on the structure of fully developed pipe flow are studied numerically by solving the Reynolds averaged Navier-Stokes equations. Linear and nonlinear k-ε or k-ω low-Re models of turbulence are used for “closing” the system of the governing equations. Computed results are compared satisfactorily against experimental measurements. Analytical results, based on boundary layer assumptions and the mixing length concept, provide a law of the wall for pipe flow under the influence of low suction rates. The analytical solution is found in satisfactory agreement with computed and experimental data for a suction rate of A = 0.46 percent. For the much higher rate of A = 2.53 percent the above assumptions are not valid and analytical velocities do not follow the computed and experimental profiles, especially in the near-wall region. Near-wall velocities, as well as the boundary shear stress, are increased with increasing suction rates. The excess wall shear stress, resulting from suction, is found to be 1.5 to 5.5 times the respective one with no suction. The turbulence levels are reduced with the presence of the wall suction. Computed results of the turbulent shear stress uv are in close agreement with experimental measurements. The distribution of the turbulent kinetic energy k is predicted better by the k-ω model of Wilcox (1993). Nonlinear models of the k-ε and k-ω type predict the reduction of the turbulence intensities u’, v’, w’, and the correct levels of v’ and w’ but they underpredict the level of u’.
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Bar-Haim, B., and D. Weihs. "Boundary Layer Flow Over Long Cylinders With Suction." Journal of Applied Mechanics 52, no. 1 (March 1, 1985): 203–7. http://dx.doi.org/10.1115/1.3168998.
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The full, axisymmetric boundary layer equations over a long circular cylinder have been repeatedly solved in the past by a variety of approximate Pohlhausen-type and series expansion methods. These methods are not suitable however, for axisymmetric solutions with wall suction boundary condition. In the present paper, the basic equations are solved by a simple approximate method, based on successive derivatives of the wall compatibility condition. A family of velocity profiles, which coincides with the asymptotic suction profile at infinity, is assumed, and the wall shear force is found by integrating an ordinary differential equation. The computed boundary layer properties for the impermeable (zero-suction) cylinder case are shown to be in good agreement with solutions of other, more sophisticated techniques. The case of an infinite cylinder with constant suction asymptotically approaches the well-known constant thickness boundary layer solution, in analogy with the case of constant suction on a flat plate. The present method is further explored to exhibit the drag reduction properties of wall suction. An optimal suction profile is found, as a function of free stream conditions and the cylinder fineness ratio. For example, in the case of a cylinder fineness ratio 5, and Re = 25 × 106, the flow can be laminarized with only 80 percent of the mass sucked off, relative to uniform suction.
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EISNER, PERRY. "Meconium Suctioning." Pediatrics 80, no. 3 (September 1, 1987): 461. http://dx.doi.org/10.1542/peds.80.3.461a.
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In Reply.— The technique that I described is briefly as follows. The finger device is removed from a standard suction catheter and attached to a 3.0- or 3.5-mm endotracheal tube after removing the endotracheal tube's adaptor. The infant is intubated with this endotracheal tube and the wall suction tubing is attached with low wall suction applied. The technique has two advantages over Dr Beck's procedure. Although they both are effective means of removing meconium without risk to the resuscitator, the delivery room must first be stocked with a 10-F semistiff suction catheter with a side suction control valve.
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Zhao, Xiao Yang, Rong Liu, Ke Wang, and Jun Hu He. "Analysis and Experiments on Pulse Vibrating Suction Method for Wall Climbing Robot." Advanced Materials Research 201-203 (February 2011): 1837–44. http://dx.doi.org/10.4028/www.scientific.net/amr.201-203.1837.
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This template explains and demonstrates how to prepare your camera-ready paper for In this paper, the pulse vibrating suction method (PVSM) for wall climbing robot is presented, which is based on the principle of vibrating suction method. To analyze this method in depth and evaluate its performance, a simplified mathematical model based on some assumptions is built, and a new experimental platform for single suction cup is developed as well. Experiments on single suction cups indicate that the experimental results match the mathematical model well with only small deviation, which is caused by some unknown factors. Then experiments are carried out on a vibrating suction module which was developed previously. With the PVSM, the suction module can stay on the wall stabely, which verifies the vadality of this vibrating method. Suction failures for the module are also analyzed with different control parameters.
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Kruse, Tamara, Sharon Wahl, Patricia Finch Guthrie, and Sue Sendelbach. "Place Atrium to Water Seal (PAWS): Assessing Wall Suction Versus No Suction for Chest Tubes After Open Heart Surgery." Critical Care Nurse 37, no. 4 (August 1, 2017): 17–28. http://dx.doi.org/10.4037/ccn2017269.
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BACKGROUND Traditionally chest tubes are set to −20 cm H2O wall suctioning until removal to facilitate drainage of blood, fluid, and air from the pleural or mediastinal space in patients after open heart surgery. However, no clear evidence supports using wall suction in these patients. Some studies in patients after pulmonary surgery indicate that using chest tubes with a water seal is safer, because this practice decreases duration of chest tube placement and eliminates air leaks. OBJECTIVE To show that changing chest tubes to a water seal after 12 hours of wall suction (intervention) is a safe alternative to using chest tubes with wall suction until removal of the tubes (usual care) in patients after open heart surgery. METHODS A before-and-after quality improvement design was used to evaluate the differences between the 2 chest tube management approaches in chest tube complications, output, and duration of placement. RESULTS A total of 48 patients received the intervention; 52 received usual care. The 2 groups (intervention vs usual care) did not differ significantly in complications (0 vs 2 events; P = .23), chest tube output (H1 = 0.001, P = .97), or duration of placement (median, 47 hours for both groups). CONCLUSION Changing chest tubes from wall suction to water seal after 12 hours of wall suction is a safe alternative to using wall suctioning until removal of the tubes.
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Antonia, R. A., L. Fulachier, L. V. Krishnamoorthy, T. Benabid, and F. Anselmet. "Influence of wall suction on the organized motion in a turbulent boundary layer." Journal of Fluid Mechanics 190 (May 1988): 217–40. http://dx.doi.org/10.1017/s0022112088001296.
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The effect of wall suction on the organized motion of a tubulent boundary layer is examined experimentally both in a wind tunnel and in a water tunnel. In the windtunnel boundary layer, which developed over a slighly heated surface, temperature fluctuations were simultaneously obtained at several points, aligned in either the x (streamwise) or y (normal to the wall) direction. The temperature traces reveal the existence of two spatially coherent events, characterized either by a sudden decrease (cooling) or by a sudden increase (heating) of temperature. Estimates are presented for the average convection velocity, and average frequency of these events. The average convection velocity of ‘coolings’ is about 15% larger than that of ‘heatings’, the velocity of both events exhibiting an important local maximum in the buffer region. Near the wall, the convection velocity of both events is increased slightly by suction while their average frequency is reduced by suction. Away from the wall, the average inclination of ‘coolings’ and ‘heatings’ is about 40° without suction; suction does not alter the inclination of ‘coolings’ but increases that of ‘heatings’ to about 50°. Visualizations in the water tunnel indicate that suction increases the stability and the longitudinal coherence of low-speed streaks. They also show that suction reduces the average frequency of dye ejections into the outer layer.
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Chandra, Peeyush, and J. S. V. R. Krishna Prasad. "Pulsatile flow in circular tubes of varying cross-section with suction/injection." Journal of the Australian Mathematical Society. Series B. Applied Mathematics 35, no. 3 (January 1994): 366–81. http://dx.doi.org/10.1017/s0334270000009358.
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AbstractWe consider here pulsatile flow in circular tubes of varying cross-section with permeable walls. The fluid exchange across the wall is accounted for by prescribing the normal velocity of the fluid at the wall. A perturbation analysis has been carried out for low Reynolds number flows and for small amplitudes of oscillation. It has been observed that the magnitude of the wall shear stress and the pressure drop decrease as the suction velocity increases. Further, as the Reynolds number is increased, the magnitude of wall shear stress increases in the convergent portion and decreases in the divergent portion of a constricted tube.
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Khalid, Mahmood, Khalid A. Juhany, and Salah Hafez. "Computational modeling of the flow in a wind tunnel." Aircraft Engineering and Aerospace Technology 90, no. 1 (January 2, 2018): 175–85. http://dx.doi.org/10.1108/aeat-05-2016-0072.
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Purpose The purpose of this paper is to use a computational technique to simulate the flow in a two-dimensional (2D) wind tunnel where the effect of the solid walls facing the model has been addressed using a porous geometry so that interference arriving at the solid walls are duly damped and a flow suction procedure has been adopted at the side wall to minimize the span-wise effect of the growing side wall boundary layer. Design/methodology/approach A CFD procedure based on discretization of the Navier–Stokes equations has been used to model the flow in a rectangular volume with appropriate treatment for solid walls of the confined volume in which the model is placed. The rectangular volume was configured by stacking O-Grid sections in a span-wise direction using geometric growth from the wall. A porous wall condition has been adapted to counter the wall interference signatures and a separate suction procedure has been implemented for reducing the side wall boundary layer effects. Findings It has been shown that through such corrective measures, the flow in a wind tunnel can be adequately simulated using computational modeling. Computed results were compared against experimental measurements obtained from IAR (Institute for Aerospace, Canada) and NAL (National Aeronautical Laboratory, Japan) to show that indeed appropriate corrective means may be adapted to reduce the interference effects. Research limitations/implications The solutions seemed to converge a lot better using relatively coarser grids which placed the shock locations closer to the experimental values. The finer grids were more stiff to converge and resulted in reversed flow with the two equation k-w model in the region where the intention was to draw out the fluid to thin down the boundary layer. The one equation Spalart–Allmaras model gave better result when porosity and wall suction routines were implemented. Practical implications This method could be used by industry to point check the results against certain demanding flow conditions and then used for more routine parametric studies at other conditions. The method would prove to be efficient and economical during early design stages of a configuration. Originality/value The method makes use of an O-grid to represent the confined test section and its dual treatment of wall interference and blockage effects through simultaneous application of porosity and boundary layer suction is believed to be quite original.
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Makinde, Oluwole Daniel, and Lazarus Rundora. "Unsteady Mixed Convection Flow of a Reactive Casson Fluid in a Permeable Wall Channel Filled with a Porous Medium." Defect and Diffusion Forum 377 (September 2017): 166–79. http://dx.doi.org/10.4028/www.scientific.net/ddf.377.166.
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In the current paper, we investigate the thermal decomposition in an unsteady mixed convection flow of a reactive Casson fluid in a vertical channel filled with a saturated porous medium. The channel walls are assumed to be permeable with fluid injection through the left wall and suction out of the right wall. There is heat dissipation caused by exothermic chemical reaction within the flow system. The dimensionless form of the momentum and energy equations will be solved numerically using a semi-discretization finite difference method and a fourth order Runge-Kutta-Fehlberg integration scheme. The influence of the Casson fluid parameter, the buoyancy parameter, the porous medium shape parameter, the Eckert number, the suction/injection Reynolds number, Frank-Kamenetskii parameter and the Prandtl number on velocity and temperature profiles, skin friction and Nusselt number as well as the thermal stability criteria are presented graphically and discussed quantitatively. It is revealed that increasing the Casson fluid parameter enhances the flow velocity, the fluid temperature and the skin friction but has a diminishing effect on the wall heat transfer rate. The suction/injection Reynolds number, the porous medium shape parameter and the buoyancy parameter enhance the rate of heat transfer at the channel walls.
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Ge, Dingxin, Yongchen Tang, Shugen Ma, Takahiro Matsuno, and Chao Ren. "A Pressing Attachment Approach for a Wall-Climbing Robot Utilizing Passive Suction Cups." Robotics 9, no. 2 (April 13, 2020): 26. http://dx.doi.org/10.3390/robotics9020026.
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This paper proposes a pressing method for wall-climbing robots to prevent them from falling. In order to realize the method, the properties of the utilized suction cup are studied experimentally. Then based on the results, a guide rail is designed to distribute the attached suction cup force and implement the pressing method. A prototype of a wall-climbing robot that utilizes passive suction cups and one motor is used to demonstrate the proposed method. An experimental test-bed is designed to measure the force changes of the suction cup when the robot climbs upwards. The experimental results validate that the suction cup can completely attach to the surface by the proposed method, and demonstrate that the robot can climb upwards without falling.
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Chung, Yongmann M., Hyung Jin Sung, and P. A. Krogstad. "Modulation of Near-Wall Turbulence Structure with Wall Blowing and Suction." AIAA Journal 40, no. 8 (August 2002): 1529–35. http://dx.doi.org/10.2514/2.1849.
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Chung, Y. M., H. J. Sung, and P. A. Krogstad. "Modulation of near-wall turbulence structure with wall blowing and suction." AIAA Journal 40 (January 2002): 1529–35. http://dx.doi.org/10.2514/3.15227.
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Bhattacharya, Avik, and A. Madhusudan Achari. "Fluid Flow Analysis Through a Variable Diameter Infra-Red Suppression Device." International Journal of Automotive and Mechanical Engineering 17, no. 1 (March 30, 2020): 7734–48. http://dx.doi.org/10.15282/ijame.17.1.2020.20.0575.
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An Infra-red suppression device(IRS) is used for suppression of heat signatures from the exhaust of the ships or aero planes, thus facilitating in the stealth operation. In the past, studies have been performed on multiple funnel type, lobed shaped as well as straight funnel type IRS device. In the present study an attempt has been made to suggest a variable diameter IRS device which works on the principle of mass suction due to drop in pressure resulting from the high velocity exhaust fluid. The multiple funnel type IRS device has been modified into an inverted fulcrum like device with holes present on the periphery of device for suction of fluid. Two types of computational studies have been performed. In the first study, the suction is occurring through the bottom as well as the holes on the periphery of funnel wall. In the second study, suction is occurring only through the holes on the funnel wall and bottom of funnel has been kept closed. The mass suction ratio has been calculated for varying Reynolds number (3000≤ R ≤ 7000). The effect on suction due to position of holes, number of holes and distance of the holes from the nozzle, effect of bidirectional flow etc. has been computed. It is found that the mass suction ratio is more when suction is occurring through the bottom of the funnel along with the holes on the funnel wall periphery.
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Opanuga, Abiodun A., Jacob A. Gbadeyan, Olasumbo O. Agboola, and Hilary I. Okagbue. "Effect of Suction/Injection on the Entropy Generation of Third Grade Fluid with Convective Cooling." Defect and Diffusion Forum 384 (May 2018): 21–30. http://dx.doi.org/10.4028/www.scientific.net/ddf.384.21.
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Effect of suction/injection on the rate of entropy generation of third grade fluid with convective cooling is analysed in this work. The highly non-linear boundary value problems obtained from the governing equations are solved by Adomian decomposition method (ADM). Some plots are presented to explain the influence of pertinent parameters on fluid motion, temperature, entropy generation and irreversibility ratio. From the results it is shown that suction/injection and third grade fluid parameters reduce fluid velocity across the channel, and increase in suction/injection parameter enhances fluid temperature while convective cooling parameter reduces it. Entropy generation is enhanced by suction/injection parameter at the lower wall but reduces it at the upper wall
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Gre´goire, G., M. Favre-Marinet, and F. Julien Saint Amand. "Modeling of Turbulent Fluid Flow Over a Rough Wall With or Without Suction." Journal of Fluids Engineering 125, no. 4 (July 1, 2003): 636–42. http://dx.doi.org/10.1115/1.1593705.
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The turbulent flow close to a wall with two-dimensional roughness is computed with a two-layer zonal model. For an impermeable wall, the classical logarithmic law compares well with the numerical results if the location of the fictitious wall modeling the surface is considered at the top of the rough boundary. The model developed by Wilcox for smooth walls is modified to account for the surface roughness and gives satisfactory results, especially for the friction coefficient, for the case of boundary layer suction.
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Schnitzlein, K. "A Note on Laminar Flow in Uniformly Porous Tubes." Journal of Fluids Engineering 115, no. 3 (September 1, 1993): 493–96. http://dx.doi.org/10.1115/1.2910165.
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A numerical analysis of the steady, laminar, incompressible flow in a constant diameter tube with uniform mass suction at the wall is made to study the development of the flow for the entire range of wall Reynolds numbers. It is shown that for small suction rates the state of flow can reach the similarity condition at least at distinct positions at the tube axis. For higher suction rates similarity profiles are found to occur only if the flow exhibits an asymmetric behavior with respect to the point of complete mass extraction.
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Aly, Emad H., U. S. Mahabaleshwar, T. Anusha, and I. Pop. "Exact Solutions for Wall Jet Flow of Hybrid Nanofluid." Journal of Nanofluids 11, no. 3 (June 1, 2022): 373–82. http://dx.doi.org/10.1166/jon.2022.1845.
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Hybrid nanofluid wall jet problem of Glauert type has been investigated under effects of the thermal radiation, suction parameter, moving parameter, slip velocity and temperature jumps. Via similarity variables governing equations are converted to system of ODEs. Then, resulted equations are solved exactly for velocity and temperature field in the view of gamma and hypergeometric functions. Further, to confirm the similarity solutions, a relationship between the free stream velocity, slip parameter along with suction parameter, moving parameter and solid volume fractions were introduced. In addition, we discussed the physical existence of the slip parameter and asymptotic behavior in a relation with the moving and suction parameters. Further, the obtained outputs are matched with the previous works. It is seen that adding the copper nanoparticles to the nanofluid titanium dioxide/water has effective part in the velocity behavior. Moreover, they warm the hybrid nanofluid on increasing the thermal radiation parameter. However, effects of suction and temperature jump parameters lead to cooling the hybrid nanofluid temperature. Furthermore, for enlarging the wall velocity, the hybrid nanofluid is much better rather than the classical nanofluid. The current analysis has important applications; such as liquid crystal solidification and polymer process.
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Josyula Venkata, Ramana Murthy, and Pavankumar Reddy Muduganti. "Hall effect on steady mhd flow and heat transfer of a viscous fluid in a rectangular channel with suction and injection." E3S Web of Conferences 128 (2019): 07008. http://dx.doi.org/10.1051/e3sconf/201912807008.
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The flow of an incompressible viscous fluid under the influence of an applied uniform magnetic field in a rectangular channel with suction at the adjacent two side walls is studied by considering Hall current and Joule heating effects. The rectangular channel is subjected to a uniform suction from top wall and injection from right wall. An external uniform magnetic field is applied perpendicular tothe flow. Two sides (left and bottom) of the channel are kept at two constant but different temperature and other two sides (right and top) are maintained at constant heat flux. Viscous and Joule dissipations are considered in the energy equation. The relevant equations of motion are solved numericallyto yield the velocity and the temperature distribution. The current density is also studied
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Mohamad Alif Ismail, Mohamad Hidayad Ahmad Kamal, Lim Yeou Jiann, Anati Ali, and Sharidan Shafie. "Transient Free Convection Mass Transfer of Second-grade Fluid Flow with Wall Transpiration." CFD Letters 13, no. 11 (November 11, 2021): 35–52. http://dx.doi.org/10.37934/cfdl.13.11.3552.
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The study of mass transfer in the non-Newtonian fluid is essential in understanding the engine lubrication, the cooling system of electronic devices, and the manufacturing process of the chemical industry. Optimal performance of the practical applications requires the appropriate conditions. The unsteady transient free convective flow of second-grade fluid with mass transfer and wall transpiration is concerned in the present communication. The behavior of the second-grade fluid under the influence of injection or suction is discussed. Suitable non-dimensional variables are utilized to transform the governing equations into non-dimensional governing equations. A Maple solver “pdsolve” that is using the centered implicit scheme of a finite difference method is utilized to solve the dimensionless governing equations numerically. The effects of wall injection or suction parameter, second-grade fluid viscoelastic parameter, Schmidt number, and modified Grashof number on the velocity and concentration profiles are graphically displayed and analyzed. The results show that with increasing wall suction, viscoelastic parameter, and Schmidt number, the velocity and concentration profiles decrease. Whereas, the velocity profiles show an opposite tendency in situations of wall injection. The wall suction has increased the skin friction and also the rate of mass diffusion in the second-grade fluid.
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Khapko, T., P. Schlatter, Y. Duguet, and D. S. Henningson. "Turbulence collapse in a suction boundary layer." Journal of Fluid Mechanics 795 (April 14, 2016): 356–79. http://dx.doi.org/10.1017/jfm.2016.205.
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Turbulence in the asymptotic suction boundary layer is investigated numerically at the verge of laminarisation using direct numerical simulation. Following an adiabatic protocol, the Reynolds number $Re$ is decreased in small steps starting from a fully turbulent state until laminarisation is observed. Computations in a large numerical domain allow in principle for the possible coexistence of laminar and turbulent regions. However, contrary to other subcritical shear flows, no laminar–turbulent coexistence is observed, even near the onset of sustained turbulence. High-resolution computations suggest a critical Reynolds number $Re_{g}\approx 270$, below which turbulence collapses, based on observation times of $O(10^{5})$ inertial time units. During the laminarisation process, the turbulent flow fragments into a series of transient streamwise-elongated structures, whose interfaces do not display the characteristic obliqueness of classical laminar–turbulent patterns. The law of the wall, i.e. logarithmic scaling of the velocity profile, is retained down to $Re_{g}$, suggesting a large-scale wall-normal transport absent in internal shear flows close to the onset. In order to test the effect of these large-scale structures on the near-wall region, an artificial volume force is added to damp spanwise and wall-normal fluctuations above $y^{+}=100$, in viscous units. Once the largest eddies have been suppressed by the forcing, and thus turbulence is confined to the near-wall region, oblique laminar–turbulent interfaces do emerge as in other wall-bounded flows, however only transiently. These results suggest that oblique stripes at the onset are a prevalent feature of internal shear flows, but will not occur in canonical boundary layers, including the spatially growing ones.
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BECK, ROBERT. "Meconium Suctioning." Pediatrics 80, no. 3 (September 1, 1987): 461. http://dx.doi.org/10.1542/peds.80.3.461.
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To the Editor.— With reference to Dr Eisner's comment (Pediatrics 1986;78:713) that it is technically difficult to intubate a neonate's trachea with a large suction catheter, I would reply that our neonatology group has enjoyed good success in suctioning meconium from below the cords in more than 1,600 meconium deliveries during the past 2 years using wall suction and a 10-F semistiff suction catheter with a side suction control valve (Superior suction catheter, Cumberland, RI).
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Vigdorovich, Igor I. "ASYMPTOTIC SUCTION TURBULENT BOUNDARY LAYER PARAMETERS CALCULATION BASED ON DATA KNOWN FOR AN IMPERMEABLE PLATE(Wall Jet and Wall Flow)." Proceedings of the International Conference on Jets, Wakes and Separated Flows (ICJWSF) 2005 (2005): 97–101. http://dx.doi.org/10.1299/jsmeicjwsf.2005.97.
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Sharma, Sheel, John A. Perrotti, and Michael T. Longaker. "Traumatic Abdominal Wall Pseudolipoma following Suction-Assisted Lipectomy." Plastic & Reconstructive Surgery 105, no. 7 (June 2000): 2589. http://dx.doi.org/10.1097/00006534-200006000-00049.
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Arnal, D., J. C. Juillen, J. Reneaux, and G. Gasparian. "Effect of wall suction on leading edge contamination." Aerospace Science and Technology 1, no. 8 (December 1997): 505–17. http://dx.doi.org/10.1016/s1270-9638(97)90000-6.
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Nichter, Larry S., John F. Reinisch, and David T. Morwood. "The Use of Wall Suction as a Lipoaspirator." Annals of Plastic Surgery 21, no. 3 (September 1988): 261–63. http://dx.doi.org/10.1097/00000637-198809000-00014.
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Deguchi, Kengo, Naoyoshi Matsubara, and Masato Nagata. "Suction–shear–Coriolis instability in a flow between parallel plates." Journal of Fluid Mechanics 760 (November 4, 2014): 212–42. http://dx.doi.org/10.1017/jfm.2014.600.
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AbstractA rotating fluid flow between differentially translating parallel plates, which induce uniform suction and injection, is studied as a canonical model of swirling flow where suction, shear and Coriolis effects compete. This relatively simple modelling yields several reduced equations that are valid for asymptotically large suction, shear and/or rotation rates. The linear stability problems derived from the full Navier–Stokes and reduced problems are numerically solved and compared. In addition to Taylor-vortex modes, transverse-roll-type instabilities are found in Rayleigh-stable and -unstable parameter regions when weak suction is applied. These instabilities, separated by the so-called Rayleigh line, are characterised by vortices attached to the suction wall. Another type of instability, which exists beyond the Rayleigh line and shows inviscid motion in the fluid core, is found when suction is sufficiently strong. The relation of this instability to the stability results by Gallet, Doering & Spiegel (Phys. Fluids, vol. 22, 2010, 034105) is discussed. Our nonlinear analyses indicate subcritical and supercritical bifurcations of finite-amplitude solutions for the near-wall and fluid-core instabilities, respectively.
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Li, Rong Jian, Hao Duan, Wen Zheng, and Hai Tao Li. "The Stability of Unsaturated Soil Foundation Pit Reinforced with the Cement-Mixed Sheet Pile Wall." Applied Mechanics and Materials 142 (November 2011): 243–46. http://dx.doi.org/10.4028/www.scientific.net/amm.142.243.
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The non-uniform distribution of matric suction in the unsaturated soil has a great impact on the stability of the unsaturated soil foundation pit. By means of the strength reduction finite element method, the stability of the unsaturated soil foundation pit reinforced with the cement-mixed sheet pile wall was analyzed. The overall safety factor of the unsaturated soil foundation pit reinforced with the cement-mixed sheet pile wall is greatly reduced and the position of potential sliding surface goes upward with the gradually decreasing of matric suction. With the constant height of the cement-mixed sheet pile wall, the shallower the embedding depth of the cement-mixed sheet pile wall is, the smaller the safety factor of the foundation pit slope is. The results show that the safety factor of the overall stability of the unsaturated soil foundation pit decreases with the deep excavation and the gradually decreasing of the matric suction.
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Lehmkuhl, Jan, Stephan Kelm, Matteo Bucci, and Hans-Josef Allelein. "Improvement of wall condensation modeling with suction wall functions for containment application." Nuclear Engineering and Design 299 (April 2016): 105–11. http://dx.doi.org/10.1016/j.nucengdes.2015.08.002.
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Singh, Desh Pal, Saurabh Goel, and Surendra Kumar. "A comparative study of negative suction drainage in inguinal hernia operations at Saraswathi Institute of Medical Sciences, Pilkhua, Hapur Uttar Pradesh." International Surgery Journal 9, no. 1 (December 28, 2021): 169. http://dx.doi.org/10.18203/2349-2902.isj20215151.
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Background: The inguinal area is the weakest region of the abdominal wall. So, this is the most common site for the development of hernias. Inguinal hernias are the commonest amongst all the hernias and hernia repair is the most frequently done operation worldwide. There is no agreement among surgeons regarding the need for drains. Some use sparingly and some use it routinely. This study aims to evaluate the use of negative suction drain in inguinal hernia surgery.Methods: We studied sixty patients of inguinal hernias both direct and indirect for one year and followed up for next 1-2 years. This prospective study aimed to see the effect of negative suction drainage in hernia surgery.Results: Both the groups did well postoperatively. It was beneficial to put a negative suction drain in those patients who had a bigger hernia, fatty patients with the thick fatty lower abdominal wall and older patients.Conclusion: It is advisable to put a negative suction drain in inguinal hernia surgery and strongly advocated if the dissection had been difficult, old patients and fatty lower abdominal wall
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Mehmood, Ahmer, Ghulam Dastgir Tabassum, Muhammad Usman, and Aman-ullah Dar. "Unsteady Self-similar Flow over an Impulsively Started Shrinking Sheet: Flow Augmentation with No Separation." International Journal of Nonlinear Sciences and Numerical Simulation 21, no. 3-4 (May 26, 2020): 319–25. http://dx.doi.org/10.1515/ijnsns-2018-0350.
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AbstractThe unsteady self-similar flow due to a permeable shrinking sheet is analyzed in this investigation. The current theoretical study is enacted in the light of correct self-similar formulation proposed by (Mehmood. A. Viscous flows: Stretching and shrinking of surfaces, Springer, 2017). For the existence of a meaningful solution the retarded boundary-layer developed due to retarded shrinking wall velocity \left( {{u_w}\left( x \right) = {{ \pm x} \over t}} \right) is supported by the sufficient mass suction introduced at the shrinking surface. Main theme of this paper is to utilize the correct mathematical formulation for the shrinking sheet flow in order to investigate the existence of dual solutions of the considered problem. By using suitable self-similar transformations, the nonlinear Navier–Stokes equations are converted to corresponding non-linear ordinary differential equations. A reliable numerical technique (shooting method) is applied to solve the resulting ODEs for the involved physical parameters. Particular to this problem, it is observed that a sufficient amount of wall suction is mandatory \left( {S \lt {S_c}; {S_c} \le 0} \right) for the existence of meaningful solutions; and also the solutions are non-unique. As the magnitude of wall suction is reduced (i. e. S \to {S_c}) the solution seizes to exist by having non-zero coefficient of wall skin-friction, reflecting the absence of any flow separation. On the other hand, a stronger flow augmentation is noted for the increasing values of the wall suction parameter S. The results are presented through graphs as well as in tabulated form. It is noticed that dual solutions exist for sufficiently large magnitude of the suction parameter\left( { \left| S \right| \gt \left| {{S_c}} \right| } \right).
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Faghri, A., and L. C. Chow. "Forced Condensation in a Tube With Suction at the Wall for Microgravitational Applications." Journal of Heat Transfer 110, no. 4a (November 1, 1988): 982–85. http://dx.doi.org/10.1115/1.3250602.
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The condensation of vapor within a tube is examined for a tube wall that has a constant temperature and uniform suction in a microgravitational environment. The motion of the condensate is due to the interfacial shear between the vapor and the liquid as well as the suction at the wall. The decrease in the vapor flow rate due to condensation has been taken into account. The governing boundary layer momentum and energy equations have been solved by approximating the convective and inertial terms. It is concluded that simultaneous suction and vapor shear can effectively drain the condensate to ensure the continuous operation of space condensers.
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Yan, Wei-Mon, and Pei-Yuan Tzeng. "Transport Phenomena of Developing Laminar Mixed Convection in Inclined Rectangular Ducts With Wall Transpiration." Journal of Heat Transfer 123, no. 4 (January 20, 2001): 810–14. http://dx.doi.org/10.1115/1.1374439.
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A numerical calculation has been carried out to investigate the mixed convection heat transfer in inclined rectangular ducts with wall transpiration. The vorticity-velocity method is employed to solve the governing equations. The present paper particularly addresses the effects of the independent parameters, namely, mixed convection parameter Δ, modified Rayleigh number Ra*, wall Reynolds number Rew and aspect ratio γ. The predicted results show that either wall injection or wall suction has a considerable impact on the flow structure and heat transfer performance. Additionally, it was found that for injection case Rew<0, the Nusselt number Nu is retarded with an increase in the wall Reynolds number Rew, but the trend is reverse for the suction flow Rew>0.
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Liu, Yixiong, Haiping He, Jixiang Gao, Gang Li, Yi Liang, and Liejun Li. "Research on the low-pressure casting process of a double suction impeller in 304 austenitic stainless steel with high performance and thin-wall complex structure." Journal of Physics: Conference Series 2390, no. 1 (December 1, 2022): 012078. http://dx.doi.org/10.1088/1742-6596/2390/1/012078.
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Abstract The manufacturing of thin-wall complex castings using pressure-assisted casting is one of the most significant challenges for structural applications requiring excellent mechanical properties and fuel. In this paper, efforts have been made to manufacture thin-wall complex structure casting using high-temperature alloys with high strength. Low pressure casting forming process was used to manufacture a double suction impeller in 304 austenitic stainless steel with a thin-wall complex structure. By combining 3D printed sand mold with an optimized low-pressure casting process, a double suction impeller with a thin-wall thickness of 3mm was successfully prepared. The prepared double suction impeller showed structural integrity, smooth surface, and compact structure. The filling and solidification process of the 304 austenitic stainless-steel melts were analyzed using casting simulation software. The casting had an excellent mechanical property with a tensile strength of 595 MPa, yield strength of 265 MPa, and elongation of 48%. Results show that the improved low-pressure casting processes could be applied to the production of thin-wall complex structure parts during high-temperature casting processes. The results are of great significance to the casting of high-temperature alloys.