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Journal articles on the topic 'Re-entrant Cavity'

Author: Grafiati
Published: 6 September 2023

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1

CALLENAERE, MATHIEU, JEAN-PIERRE FRANC, JEAN-MARIE MICHEL, and MICHEL RIONDET. "The cavitation instability induced by the development of a re-entrant jet." Journal of Fluid Mechanics 444 (September 25, 2001): 223–56. http://dx.doi.org/10.1017/s0022112001005420.

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The instability of a partial cavity induced by the development of a re-entrant jet is investigated on the basis of experiments conducted on a diverging step. Detailed visualizations of the cavity behaviour allowed us to identify the domain of the re-entrant jet instability which leads to classical cloud cavitation. The surrounding regimes are also investigated, in particular the special case of thin cavities which do not oscillate in length but surprisingly exhibit a re-entrant jet of periodical behaviour. The velocity of the re-entrant jet is measured from visualizations, in the case of both cloud cavitation and thin cavities. The limits of the domain of the re-entrant jet instability are corroborated by velocity fluctuation measurements. By varying the divergence and the confinement of the channel, it is shown that the extent of the auto-oscillation domain primarily depends upon the average adverse pressure gradient in the channel. This conclusion is corroborated by the determination of the pressure gradient on the basis of LDV measurements which shows a good correlation between the domain of the cloud cavitation instability and the region of high adverse pressure gradient. A simple phenomenological model of the development of the re-entrant jet in an adverse pressure gradient confirms the strong influence of the pressure gradient on the development of the re-entrant jet and particularly on its thickness. An ultrasonic technique is developed to measure the re-entrant jet thickness, which allowed us to compare it with the cavity thickness. By considering an estimate of the characteristic height of the perturbations developing on the interface of the cavity and of the re-entrant jet, it is shown that cloud cavitation requires negligible interaction between both interfaces, i.e. a thick enough cavity. In the case of thin cavities, this interaction becomes predominant; the cavity interface breaks at many points, giving birth to small-scale vapour structures unlike the large-scale clouds which are periodically shed in the case of cloud cavitation. The low-frequency content of the cloud cavitation instability is investigated using spectral analysis of wall pressure signals. It is shown that the characteristic frequency of cloud cavitation corresponds to a Strouhal number of about 0.2 whatever the operating conditions and the cavity length may be, provided the Strouhal number is computed on the basis of the maximum cavity length. For long enough cavities, another peak is observed in the spectra, at lower frequency, which is interpreted as a surge-type instability. The present investigations give insight into the instabilities that a partial cavity may undergo, and particularly the re-entrant jet instability. Two parameters are shown to be of most importance in the analysis of the re-entrant jet instability: the adverse pressure gradient and the cavity thickness compared to the re-entrant jet thickness. The present results allowed us to conduct a qualitative phenomenological analysis of the stability of partial cavities on cavitating hydrofoils. It is conjectured that cloud cavitation should occur for short enough cavities, of the order of half the chordlength, whereas the instability often observed at the limit between partial cavitation and super-cavitation is here interpreted as a cavitation surge-type instability.
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2

LABERTEAUX, K. R., and S. L. CECCIO. "Partial cavity flows. Part 1. Cavities forming on models without spanwise variation." Journal of Fluid Mechanics 431 (March 25, 2001): 1–41. http://dx.doi.org/10.1017/s0022112000002925.

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Partial cavities that formed on the vertices of wedges and on the leading edge of stationary hydrofoils were examined experimentally. The geometry of these test objects did not vary in the spanwise direction (i.e. two-dimensional). Open partial cavities formed on a series of two-dimensional wedges and on a plano-convex hydrofoil. These cavities terminated near the point of maximum cavity thickness, and small vapour-filled vortices were shed in the turbulent cavity wake. The turbulent flow in the wake of the open cavity was similar to the turbulent shear flow downstream of a rearward-facing step. Re-entrant flow was not observed in the cavity closure of open cavities, although recirculating flow associated with a region of flow separation was detected for some cases. Predictions of a two-dimensional free-streamline model of the cavitating wedge flows were compared to the experimentally observed cavities. The model predicted the profile of the open cavity only to the point of maximum cavity thickness. Examination of the flow field near the closure of the open cavities revealed adverse pressure gradients near the cavity closure. The pressure gradients around the open cavities were sufficient to cause large-scale condensation of the cavity. Unsteady re-entrant partial cavities formed on a two-dimensional NACA0009 hydrofoil. The interface of the unsteady closed cavities smoothly curved to form a re-entrant jet at the cavity terminus, and the re-entrant flow was directed upstream. The re-entrant flow impinged on the cavity interface and led to the periodic production of cloud cavitation. These cavities exhibited a laminar flow reattachment. The flow around the closed cavity was largely irrotational, while vorticity was created when the cloud cavitation collapsed downstream of the cavity. Examination of the flow field near closure of these cavities also revealed adverse pressure gradients near the partial cavity closure, but the rise in pressure did not lead to the premature condensation of the cavity.
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3

Tiwari, Ashish Kumar, Ramesh Kumar, and P. R. Hannurkar. "Resonant frequency of re-entrant klystron cavity." International Journal of Electronics Letters 4, no. 4 (June 15, 2015): 404–10. http://dx.doi.org/10.1080/21681724.2015.1055593.

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4

Pelz, P. F., T. Keil, and T. F. Groß. "The transition from sheet to cloud cavitation." Journal of Fluid Mechanics 817 (March 22, 2017): 439–54. http://dx.doi.org/10.1017/jfm.2017.75.

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Recent studies indicate that the transition from sheet to cloud cavitation depends on both cavitation number and Reynolds number. In the present paper this transition is investigated analytically and a physical model is introduced. In order to include the entire process, the model consists of two parts, a model for the growth of the sheet cavity and a viscous film flow model for the so-called re-entrant jet. The models allow the calculation of the length of the sheet cavity for given nucleation rates and initial nuclei radii and the spreading history of the viscous film. By definition, the transition occurs when the re-entrant jet reaches the point of origin of the sheet cavity, implying that the cavity length and the penetration length of the re-entrant jet are equal. Following this criterion, a stability map is derived showing that the transition depends on a critical Reynolds number which is a function of cavitation number and relative surface roughness. A good agreement was found between the model-based calculations and the experimental measurements. In conclusion, the presented research shows the evidence of nucleation and bubble collapse for the growth of the sheet cavity and underlines the role of wall friction for the evolution of the re-entrant jet.
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5

Deliceoğlu, Ali, Ebutalib Çelik, and Fuat Gürcan. "Singular treatment of viscous flow near the corner by using matched eigenfunctions." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 5 (May 15, 2018): 1660–76. http://dx.doi.org/10.1177/0954406218772603.

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In this paper, the local singular behavior of Stokes flow is solved near the salient and re-entrant corners by the matching eigenfunction method. The flow in a rectangular and an L-shaped cavity are considered as a model for the flow generated by the motion of the upper lid. The solutions of the Stokes equation in polar coordinates are matched with a velocity vector components obtained by analytic or numerical solution for the streamfunction developed for any values of the heights of the rectangular and an L-shaped cavity. Streamline patterns near the corner are simulated for a different aspect ratio A. The techniques are tested on a flow problem undergoing Stokes or Navier–Stokes equations in a square cavity. It is seen that the method appears to be cheaper and more accurate than the numerical and analytical methods. It is expected that the study will lead to useful insights into the understanding of the flow topology near a re-entrant corner from a combined analytical-numerical method. Attention is then focused on the topological behavior near the re-entrant corner of the L-shaped cavity. Careful analysis of the streamlines of streamfunction near the re-entrant corner by using wall shear stress allows us to give a possible flow bifurcation of dividing streamline.
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6

Dang, J., and G. Kuiper. "Re-Entrant Jet Modeling of Partial Cavity Flow on Three-Dimensional Hydrofoils." Journal of Fluids Engineering 121, no. 4 (December 1, 1999): 781–87. http://dx.doi.org/10.1115/1.2823537.

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A potential-based lower-order surface panel method is developed to calculate the flow around a three-dimensional hydrofoil with an attached sheet cavity the leading edge. A Dirichlet type dynamic boundary condition on the cavity surface and a Neumann boundary condition on the wetted surface are enforced. The cavity shape is initially assumed and the kinematic boundary condition on the cavity surface is satisfied by iterating the cavity length and shape. Upon convergence, both the dynamic boundary condition and the kinematic boundary condition on the cavity surface are satisfied, and a re-entrant jet develops at the cavity closure. The flow at the closure of the cavity and the mechanism of the re-entrant jet formation is investigated. Good agreement is found between the calculated results and MIT’s experiments on a 3-D hydrofoil.
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7

Kalhori, Shirzad, Nils Elander, Jan Svennebrink, and Sharon Stone-Elander. "A Re-Entrant Cavity for Microwave-Enhanced Chemistry." Journal of Microwave Power and Electromagnetic Energy 38, no. 2 (January 2003): 125–35. http://dx.doi.org/10.1080/08327823.2003.11688493.

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8

Pandit, Himanshu, Donglu Shi, N. Hari Babu, X. Chaud, D. A. Cardwell, P. He, D. Isfort, Robert Tournier, David Mast, and Altan M. Ferendeci. "High Tc superconductor re-entrant cavity filter structures." Physica C: Superconductivity 425, no. 1-2 (September 2005): 44–51. http://dx.doi.org/10.1016/j.physc.2005.05.010.

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9

Sangster, A. J., E. McErlean, G. Beale, M. Kelly, and P. Smith. "Coupled Re-Entrant Cavity System for Electromagnetic Levitation." Journal of Electromagnetic Waves and Applications 15, no. 6 (January 2001): 815–31. http://dx.doi.org/10.1163/156939301x01048.

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10

Zang, Jianbo, Hu Zhang, Jiean Shen, and Yaoyao Wang. "Analysis of cavity shedding around the twisted hydrofoil." Thermal Science, no. 00 (2022): 180. http://dx.doi.org/10.2298/tsci220606180z.

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In order to understand the mechanism of cavity shedding and evolution, turbulent cavitating flows of the twisted hydrofoil were numerically investigated using the k-? turbulence model and the ZGB cavitation model. The results of the numerical calculation and the experimental method are basically consistent, which confirms the feasibility of the numerical calculation model. This study has obtained the following conclusions. Firstly, the cavity shedding can be summarized into six stages, and the cavity shape, pressure and velocity field at different stages are displayed, analyzed and compared in detail. Secondly, the shedding of cavity and its evolution are mainly caused by the re-entrant jet and side-entrant jet, in which the former provides the kinetic energy and the latter plays the role of guiding the direction. Thirdly, under the convective shearing action of the re-entrant jet and the main flow, a strong vortex located in the mid-back edge of the hydrofoil is formed, which promotes the transformation of the cavity shape into a U-shaped structure.
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11

LABERTEAUX, K. R., and S. L. CECCIO. "Partial cavity flows. Part 2. Cavities forming on test objects with spanwise variation." Journal of Fluid Mechanics 431 (March 25, 2001): 43–63. http://dx.doi.org/10.1017/s0022112000002937.

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Partial cavitation forming on the vertex of a wedge and on the leading edge of a stationary hydrofoil was experimentally examined. The geometry of these test objects varied in the spanwise direction (i.e. three-dimensional test objects). Closed cavities formed on these test objects. The interface of the closed cavities curved smoothly to form a re-entrant jet at the cavity terminus, and the re-entrant flow was directed spanwise, thus preventing its impingement on the cavity interface. The cavity shape and the pressure gradients near the closure of the closed cavities were qualitatively similar to those predicted with the two-dimensional free-streamline theory. These cavities had a steady, laminar flow reattachment. The flow around the closed cavity was largely irrotational.
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12

Chen, Jie, Chang-Chang Wang, Guoyu Wang, and Biao Huang. "Numerical investigation of the cavitating flow structure with special emphasis on the vortex identification method." Modern Physics Letters B 34, no. 04 (January 31, 2020): 2050058. http://dx.doi.org/10.1142/s021798492050058x.

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The three kinds of vortex identification methods, namely, [Formula: see text] criterion, [Formula: see text] criterion and [Formula: see text] method, are then employed to investigate the physical interactions between the cavitation and vortex dynamics around two-dimensional Clark-Y hydrofoil. The results show that compared to the [Formula: see text] and [Formula: see text] criterion, the [Formula: see text] method can capture the vortex structures with both strong and weak vortices, especially for the weak vortices located in the boundary of the cavity and the back region of the re-entrant flow. A proper value of [Formula: see text] in [Formula: see text] method based on the previous studies is then suggested to avoid the pseudo-vortex structure in cavitating flow field due to division by zero. The modified [Formula: see text] method with a proper [Formula: see text] is then applied to analyze the details of vortical structures in the growth of attached cavity, the re-entrant flow development stage and the cloud cavity shedding stage. The results show that the vortical structures are captured in the boundary and rear region of the attached cavity, the intensity and complexity of strong vortices in the rear boundary region of re-entrant flow increased with its development, and the strength and area of vortical structures at the trailing edge of hydrofoil increased with propulsion of cloud cavity before it sheds completely.
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13

Mohammed, Ali Musa, Yi Wang, Talal Skaik, Sheng Li, and Moataz Attallah. "Conductivity measurement using 3D printed re-entrant cavity resonator." Measurement Science and Technology 33, no. 5 (February 18, 2022): 055017. http://dx.doi.org/10.1088/1361-6501/ac5134.

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Abstract A technique for measuring effective conductivity of conductor materials using 3D printed re-entrant cavity resonator is proposed. An analytical formula for the extraction of the effective conductivity has been derived in relation to energy stored in the volume of the cavity geometry. A method of resonant cavity characterisation of material based on microwave losses is utilised for the measurements. The approach offers a simplified analytical method and also supports the measurements of sample with arbitrary thickness. Samples produced from three different manufacturing processes of computer numerical control (CNC) and 3D printing, made of aluminium, copper and stainless steel were measured to demonstrate the method. The 3D printed and copper coated polymer sample is considered as reference material for the measurements. The measured results have shown that the copper coated polymer sample have similar conductivity with that CNC copper. This signifies the good finishing, low surface roughness and quality of copper coating used in 3D printed polymer device.
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14

Kawanami, Y., H. Kato, H. Yamaguchi, M. Tanimura, and Y. Tagaya. "Mechanism and Control of Cloud Cavitation." Journal of Fluids Engineering 119, no. 4 (December 1, 1997): 788–94. http://dx.doi.org/10.1115/1.2819499.

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Generation mechanism of cloud cavitation on a hydrofoil section was investigated in a sequence of experiments through observation of cloud cavitation by high-speed video and high-speed photo as well as pressure measurements by pressure pick-ups and a hydrophone. The mechanism was also investigated by controlling cloud cavitation with an obstacle fitted on the foil surface. From the results of these experiments, it was found that the collapse of a sheet cavity is triggered by a re-entrant jet rushing from the trailing edge to the leading edge of the sheet cavity, and consequently, the sheet cavity is shed in the vicinity of its leading edge and thrown downstream as a cluster of bubbles called cloud cavity. In other words, the re-entrant jet gives rise to cloud cavitation. Moreover, cloud cavitation could be controlled effectively by a small obstacle placed on the foil. It resulted in reduction of foil drag and cavitation noise.
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15

Hamzah, Hayder, Ali Abduljabar, Jonathan Lees, and Adrian Porch. "A Compact Microwave Microfluidic Sensor Using a Re-Entrant Cavity." Sensors 18, no. 3 (March 19, 2018): 910. http://dx.doi.org/10.3390/s18030910.

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16

Hemawan, Kadek W., Indrek S. Wichman, Tonghun Lee, Timothy A. Grotjohn, and Jes Asmussen. "Compact microwave re-entrant cavity applicator for plasma-assisted combustion." Review of Scientific Instruments 80, no. 5 (May 2009): 053507. http://dx.doi.org/10.1063/1.3131623.

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17

Kelly, M. B., and A. J. Sangster. "Cylindrical re-entrant cavity resonator design using finite-element simulation." Microwave and Optical Technology Letters 18, no. 2 (June 5, 1998): 112–17. http://dx.doi.org/10.1002/(sici)1098-2760(19980605)18:2<112::aid-mop8>3.0.co;2-d.

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18

Dang, J., and G. Kuiper. "Re-Entrant Jet Modeling of Partial Cavity Flow on Two-Dimensional Hydrofoils." Journal of Fluids Engineering 121, no. 4 (December 1, 1999): 773–80. http://dx.doi.org/10.1115/1.2823536.

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A potential based panel method is developed to predict the partial cavity flow on two-dimensional hydrofoil sections. The Dirichlet type dynamic boundary condition on the cavity surface and the Neumann type kinematic boundary condition on the wetted section surface are enforced. A re-entrant jet cavity termination model is introduced. A validation is accomplished by comparing the present calculations with cavitation experiments of a modified Joukowsky foil and a NACA 66(MOD) a = 0.8 section.
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19

Zhang, Desheng, Jian Chen, Lei Shi, Guangjian Zhang, Weidong Shi, and van Esch. "Numerical analysis of the unsteady cavitation shedding flow around twisted hydrofoil based on hybrid filter model." Thermal Science 22, no. 4 (2018): 1629–36. http://dx.doi.org/10.2298/tsci1804629z.

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Cavitation is a common phenomenon in components of fluid machinery and it may induce material damage and vibration. A more accurate and commercial turbulence model is required to predict cavitation. In this paper, we make a combination of filter-based model (FBM) and density correction method (DCM) to propose a new DCM FBM. Firstly, the new DCM FBM and the homogeneous cavitation model are validated by comparing the simulation result with the experiment of cavitation shedding flow around the Clark-y hydrofoil and the filter size is determined as well. Then, the cavitation pattern cycle and shedding vortex structure of the twist hydrofoil experimented by Delft University of Technology were predicted using the DCM FBM. The predicted 3-D cavitation structures and development cycle of twist hydrofoil as well as the collapsing features show a good qualitative agreement with the high speed photography results. Numerical results show that the improved turbulence model could predict the cloud cavity evolution well, including the cloud cavity generation, shedding and dissipation. It is found that the re-entrant jet induced by the by adverse pressure gradient is the main reason to generate the cloud cavity shedding. The secondary shedding is al-so observed which is result from the combination of the radially advancing re-entrant jet and side-entrant jet simulated by the DCM FBM turbulence method.
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20

Li, Jiupeng, Yu Zhang, Yanlin Ke, Tianzeng Hong, and Shaozhi Deng. "A Carbon-Nanotube Cold-Cathode Reflex Klystron Oscillator: Fabrication @ X-Band and Returning Electron Beam Realization." Electronics 11, no. 8 (April 13, 2022): 1231. http://dx.doi.org/10.3390/electronics11081231.

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This paper presents the design and fabrication of a reflex klystron oscillator based on a carbon nanotube (CNT) cold-cathode. An X-band klystron oscillator structure is assembled with a CNT cold-cathode electron gun with an electrostatic focusing, a re-entrant cavity as anode, and a repeller. The electron gun adopts a convex CNT film emitter as the cathode. A re-entrant cavity resonating at 8.376 GHz is fabricated. The study mainly focuses on the returning electron beam in the klystron oscillator structure. The experimental results of variations of the anode current and returning electron beam amplitude with repeller voltage are presented. It is demonstrated that a higher extracting voltage of the cold-cathode has an important influence on the returning electron beam. To decelerate electron velocity from the extracting voltage, increasing negative focusing voltage and focusing electrode height in the electron gun can improve the returning electron beam characteristics.
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21

Giunchi, G., A. Figini Albisetti, C. Braggio, G. Carugno, G. Messineo, G. Ruoso, G. Galeazzi, and F. Della Valle. "A Re-Entrant ${\hbox{MgB}}_{2}$ Cavity for Dynamic Casimir Experiment." IEEE Transactions on Applied Superconductivity 21, no. 3 (June 2011): 745–47. http://dx.doi.org/10.1109/tasc.2010.2097575.

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22

Kartikeyan, M. V., L. M. Joshi, A. K. Sinha, H. N. Bandopadhyay, and D. S. Venkateswarlu. "Computer Aided Study of Some Re-entrant Cavity Structures for Klystrons." IETE Journal of Research 39, no. 6 (November 1993): 339–44. http://dx.doi.org/10.1080/03772063.1993.11437144.

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23

Wei, Zhihua, Jie Huang, Jing Li, Junshan Li, Xuyang Liu, and Xingsheng Ni. "A Compact Double-Folded Substrate Integrated Waveguide Re-Entrant Cavity for Highly Sensitive Humidity Sensing." Sensors 19, no. 15 (July 27, 2019): 3308. http://dx.doi.org/10.3390/s19153308.

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In this study, an ultra-compact humidity sensor based on a double-folded substrate integrated waveguide (SIW) re-entrant cavity was proposed and analyzed. By folding a circular re-entrant cavity twice along its two orthogonally symmetric planes, the designed structure achieved a remarkable size reduction (up to 85.9%) in comparison with a conventional TM010-mode circular SIW cavity. The operating principle of the humidity sensor is based on the resonant method, in other words, it utilizes the resonant properties of the sensor as signatures to detect the humidity condition of the ambient environment. To this end, a mathematical model quantitatively relating the resonant frequency of the sensor and the relative humidity (RH) level was established according to the cavity perturbation theory. The sensing performance of the sensor was experimentally validated in a RH range of 30%–80% by using a humidity chamber. The measured absolute sensitivity of the sensor was calculated to be 135.6 kHz/%RH, and the corresponding normalized sensitivity was 0.00627%/%RH. It was demonstrated that our proposed sensor not only has the merits of compact size and high sensitivity, but also benefits from a high Q-factor and ease of fabrication and integration. These advantages make it an excellent candidate for humidity sensing applications in various fields such as the agricultural, pharmaceutical, and food industries.
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24

Zhao, Yu, Guoyu Wang, and Biao Huang. "Vortex structure analysis of unsteady cloud cavitating flows around a hydrofoil." Modern Physics Letters B 30, no. 02 (January 20, 2016): 1550275. http://dx.doi.org/10.1142/s0217984915502759.

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In this paper, time dependent vortex structures are numerically analyzed for both noncavitating and cloud cavitating flows around a Clark-Y hydrofoil with angle of attack [Formula: see text] at a moderate Reynolds number, [Formula: see text]. The numerical simulations are performed using a transport equation-based cavitation model and the large eddy simulation (LES) approach with a classical eddy viscosity subgrid scale (SGS) model. Compared with experimental results, present numerical predictions are capable of capturing the initiation of cavity, growth toward the trailing edge and subsequent shedding process. Results indicate that in noncavitating conditions, the trailing edge vortex and induced positive vortex shed periodically into the wake region to form the vortex street. In cloud cavitating conditions, interrelations between cavity and vortex induce different vortex dynamics at different cavity developing stages. (i) As attached cavity grows, vorticity production is greatly enhanced by the favorable pressure gradient at the leading edge. The trailing edge flow does not have a direct impact on the attached cavity expansion process. Furthermore, the liquid–vapor interface that moves toward the trailing edge enhances the vorticity in the attached cavity closure region. (ii) When the stable attached sheet cavity grows to its maximum length, the accumulation process of vorticity is eventually interrupted by the formation of the re-entrant jet. Re-entrant jet’s moving upstream leads to a higher spreading rate of the attached cavity and the formation of a large coherent structure inside the attached cavity. Moreover, the wavy/bubbly cavity interface enhances the vorticity near the trailing edge. (iii) As the attached sheet cavity breaks up, this large vortex structure converts toward the trailing edge region, which will eventually couple with a trailing edge vortex shedding from the lower surface to form the cloud cavity. The breakup of the stable attached cavity is the main reason for the vorticity enhancement near the suction surface.
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25

Kumar, Sumit, Sebastian Spence, Simon Perrett, Zaynab Tahir, Angadjit Singh, Chichi Qi, Sara Perez Vizan, and Xavier Rojas. "A novel architecture for room temperature microwave optomechanical experiments." Journal of Applied Physics 133, no. 9 (March 7, 2023): 094501. http://dx.doi.org/10.1063/5.0136214.

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We have developed a novel architecture for room temperature microwave cavity optomechanics, which is based on the coupling of a 3D microwave re-entrant cavity to a compliant membrane. Device parameters have enabled resolving the thermomechanical motion of the membrane and observing optomechanically induced transparency/absorption in the linear regime for the first time in a microwave optomechanical system operated at room temperature. We have extracted the single-photon coupling rate ([Formula: see text]) using four independent measurement techniques and, hence, obtained a full characterization of the proposed cavity optomechanical system.
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26

Xi, W., W. R. Tinga, W. A. G. Voss, and B. Q. Tian. "New results for coaxial re-entrant cavity with partially dielectric filled gap." IEEE Transactions on Microwave Theory and Techniques 40, no. 4 (April 1992): 747–53. http://dx.doi.org/10.1109/22.127525.

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27

Menke, T., P. S. Burns, A. P. Higginbotham, N. S. Kampel, R. W. Peterson, K. Cicak, R. W. Simmonds, C. A. Regal, and K. W. Lehnert. "Reconfigurable re-entrant cavity for wireless coupling to an electro-optomechanical device." Review of Scientific Instruments 88, no. 9 (September 2017): 094701. http://dx.doi.org/10.1063/1.5000973.

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28

Phadke, N. K., S. H. Bhavnani, A. Goyal, R. C. Jaeger, and J. S. Goodling. "Re-entrant cavity surface enhancements for immersion cooling of silicon multichip packages." IEEE Transactions on Components, Hybrids, and Manufacturing Technology 15, no. 5 (1992): 815–22. http://dx.doi.org/10.1109/33.180047.

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29

Barroso, J. J., P. J. Castro, O. D. Aguiar, and L. A. Carneiro. "Experimental tests on re-entrant klystron cavity for a gravitational wave antenna." Classical and Quantum Gravity 21, no. 5 (February 13, 2004): S1221—S1224. http://dx.doi.org/10.1088/0264-9381/21/5/123.

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30

Bordoni, F., Li Yinghua, B. Spataro, F. Feliciangeli, F. Vasarelli, G. Cardarilli, B. Antonini, and R. Scrimaglio. "A microwave scanning surface harmonic microscope using a re-entrant resonant cavity." Measurement Science and Technology 6, no. 8 (August 1, 1995): 1208–14. http://dx.doi.org/10.1088/0957-0233/6/8/017.

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31

Hopkins, Matthew G., Yvonne Leusmann, Markus Richter, Eric F. May, and Paul L. Stanwix. "Characterization of Fluid-Phase Behavior Using an Advanced Microwave Re-Entrant Cavity." Journal of Chemical & Engineering Data 65, no. 7 (June 10, 2020): 3393–402. http://dx.doi.org/10.1021/acs.jced.0c00213.

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32

Linthorne, N. P., and D. G. Blair. "Superconducting re‐entrant cavity transducer for a resonant bar gravitational radiation antenna." Review of Scientific Instruments 63, no. 9 (September 1992): 4154–60. http://dx.doi.org/10.1063/1.1143227.

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33

Barbaca, Luka, Bryce W. Pearce, Harish Ganesh, Steven L. Ceccio, and Paul A. Brandner. "On the unsteady behaviour of cavity flow over a two-dimensional wall-mounted fence." Journal of Fluid Mechanics 874 (July 10, 2019): 483–525. http://dx.doi.org/10.1017/jfm.2019.455.

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The topology and unsteady behaviour of ventilated and natural cavity flows over a two-dimensional (2-D) wall-mounted fence are investigated for fixed length cavities with varying free-stream velocity using high-speed and still imaging, X-ray densitometry and dynamic surface pressure measurement in two experimental facilities. Cavities in both ventilated and natural flows were found to have a re-entrant jet closure, but not to exhibit large-scale oscillations, yet the irregular small-scale shedding at the cavity closure. Small-scale cavity break-up was associated with a high-frequency broadband peak in the wall pressure spectra, found to be governed by the overlying turbulent boundary layer characteristics, similar to observations from single-phase flow over a forward-facing step. A low-frequency peak reflecting the oscillations in size of the re-entrant jet region, analogous to ‘flapping’ motion in single-phase flow, was found to be modulated by gravity effects (i.e. a Froude number dependence). Likewise, a significant change in cavity behaviour was observed as the flow underwent transition analogous to the transition from sub- to super-critical regime in open-channel flow. Differences in wake topology were examined using shadowgraphy and proper orthogonal decomposition, from which it was found that the size and number of shed structures increased with an increase in free-stream velocity for the ventilated case, while remaining nominally constant in naturally cavitating flow due to condensation of vaporous structures.
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34

Park, Sunho, Woochan Seok, Sung Taek Park, Shin Hyung Rhee, Yohan Choe, Chongam Kim, Ji-Hye Kim, and Byoung-Kwon Ahn. "Compressibility Effects on Cavity Dynamics behind a Two-Dimensional Wedge." Journal of Marine Science and Engineering 8, no. 1 (January 13, 2020): 39. http://dx.doi.org/10.3390/jmse8010039.

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To understand cavity dynamics, many experimental and computational studies have been conducted for many decades. As computational methods, incompressible, isothermal compressible, and fully compressible flow solvers were used for the purpose. In the present study, to understand the compressibility effect on cavity dynamics, both incompressible and fully compressible flow solvers were developed, respectively. Experiments were also carried out in a cavitation tunnel to compare with the computational results. The cavity shedding dynamics, re-entrant jet, transition from bounded shear layer vortices to Karman vortices, and pressure and velocity contours behind the two-dimensional wedge by the two developed solvers were compared at various cavitation numbers.
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35

Mohammed, Ali M., Abarasi Hart, Joe Wood, Yi Wang, and Michael J. Lancaster. "3D printed re-entrant cavity resonator for complex permittivity measurement of crude oils." Sensors and Actuators A: Physical 317 (January 2021): 112477. http://dx.doi.org/10.1016/j.sna.2020.112477.

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36

Dular, Matevž, Rudolf Bachert, Christian Schaad, and Bernd Stoffel. "Investigation of a re-entrant jet reflection at an inclined cavity closure line." European Journal of Mechanics - B/Fluids 26, no. 5 (September 2007): 688–705. http://dx.doi.org/10.1016/j.euromechflu.2007.01.001.

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37

Iga, Yuka, Motohiko Nohmi, Akira Goto, Byeong Rog Shin, and Toshiaki Ikohagi. "Numerical Study of Sheet Cavitation Breakoff Phenomenon on a Cascade Hydrofoil." Journal of Fluids Engineering 125, no. 4 (July 1, 2003): 643–51. http://dx.doi.org/10.1115/1.1596239.

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Two-dimensional unsteady cavity flow through a cascade of hydrofoils is numerically calculated. Particular attention is focused on instability phenomena of a sheet cavity in the transient cavitation condition, and the mechanism of the breakoff phenomenon is examined. TVD-MacCormack’s scheme employing a locally homogeneous model of compressible gas-liquid two-phase medium is applied to analyze the cavity flows. The present method permits us to treat the entire cavitating/noncavitating unsteady flowfield. By analyzing the numerical results in detail, it becomes clear that there are at least two mechanisms in the breakoff phenomenon of the sheet cavity: one is that re-entrant jets play a dominant role in such a breakoff phenomenon, and the other is that pressure waves propagating inside the cavity bring about another type of breakoff phenomenon accompanying with cavity surface waves.
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38

Watanabe, Satoshi, Yoshinobu Tsujimoto, and Akinori Furukawa. "Theoretical Analysis of Transitional and Partial Cavity Instabilities." Journal of Fluids Engineering 123, no. 3 (March 30, 2001): 692–97. http://dx.doi.org/10.1115/1.1378295.

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This paper describes a new time marching calculation of blade surface cavitation based on a linearized free streamline theory using a singularity method. In this calculation, closed cavity models for partial and super cavities are combined to simulate the transitional cavity oscillation between partial and super cavities. The results for an isolated hydrofoil located in a 2-D channel are presented. Although the re-entrant jet is not taken into account, the transitional cavity oscillation with large amplitude, which is known to occur when the cavity length exceeds 75 percent of the chord length, was simulated fairly well. The partial cavity oscillation with relatively high frequency was simulated as damping oscillations. The frequency of the damping oscillation agrees with that of a stability analysis and of experiments. The present calculation can be easily extended to simulate other cavity instabilities in pumps or cascades.
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39

Saitoh, Yoshiaki, Jin-ichi Matsuda, and Kazuo Kato. "Characteristics of re-entrant type cavity applicator for hyperthermia. I. Experiments for heating possibility." Thermal Medicine(Japanese Journal of Hyperthermic Oncology) 7, no. 1 (1991): 42–52. http://dx.doi.org/10.3191/thermalmedicine.7.42.

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40

Balagi, V., and J. P. Singh. "A new design of a re-entrant cavity ionisation chamber for use in brachytherapy." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 578, no. 3 (August 2007): 523–27. http://dx.doi.org/10.1016/j.nima.2007.06.006.

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41

Ego, Hiroyasu. "HOM-damped re-entrant quasi-half-cell cavity for the SPring-8 storage ring." Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 516, no. 2-3 (January 2004): 270–80. http://dx.doi.org/10.1016/j.nima.2003.07.060.

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42

JI, BIN, XIANWU LUO, YULIN WU, XIAOXING PENG, and HONGYUAN XU. "NUMERICAL AND EXPERIMENTAL STUDY ON UNSTEADY SHEDDING OF PARTIAL CAVITATION." Modern Physics Letters B 24, no. 13 (May 30, 2010): 1441–44. http://dx.doi.org/10.1142/s0217984910023827.

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Periodically unsteady shedding of partial cavity and forming of cavitation cloud have a great influence on hydraulic performances and cavitation erosion for ship propellers and hydro machines. In the present study, the unsteady cavitating flow around a hydrofoil has been calculated by using the single fluid approach with a developed cavitation mass transfer expression based on the vaporization and condensation of the fluid. The numerical simulation depicted the unsteady shedding of partial cavity, such as the process of cavity developing, breaking off and collapsing in the downstream under the steady incoming flow condition. It is noted that good agreement between the numerical results and that of experiment conducted at a cavitation tunnel is achieved. The cavitating flow field indicates that the cavity shedding was mainly caused by the re-entrant jet near cavity trailing edge, which was also clearly recorded by high-speed photographing.
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43

Harwood, Casey M., Yin L. Young, and Steven L. Ceccio. "Ventilated cavities on a surface-piercing hydrofoil at moderate Froude numbers: cavity formation, elimination and stability." Journal of Fluid Mechanics 800 (June 29, 2016): 5–56. http://dx.doi.org/10.1017/jfm.2016.373.

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The atmospheric ventilation of a surface-piercing hydrofoil is examined in a series of towing-tank experiments, performed on a vertically cantilevered hydrofoil with an immersed free tip. The results of the experiments expand upon previous studies by contributing towards a comprehensive understanding of the topology, formation and elimination of ventilated flows at low-to-moderate Froude and Reynolds numbers. Fully wetted, fully ventilated and partially ventilated flow regimes are identified, and their stability regions are presented in parametric space. The stability of partially and fully ventilated regimes is related to the angle of the re-entrant jet, leading to a set of criteria for identifying flow regimes in a laboratory environment. The stability region of fully wetted flow overlaps those of partially and fully ventilated flows, forming bi-stable regions where hysteresis occurs. Ventilation transition mechanisms are classified as formation and elimination mechanisms, which separate the three steady flow regimes from one another. Ventilation formation requires air ingress into separated flow at sub-atmospheric pressure from a continuously available air source. Ventilation washout is caused by upstream flow of the re-entrant jet. The boundary denoting washout of fully ventilated flow is expressed as a semi-theoretical scaling relation, which captures past and present experimental data well across a wide range of Froude and Reynolds numbers.
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44

Zhang, De-Sheng, Guan-Gjian Zhang, Hai-Yu Wang, and Wei-Dong Shi. "Numerical investigation of time-dependent cloud cavitating flow around a hydrofoil." Thermal Science 20, no. 3 (2016): 913–20. http://dx.doi.org/10.2298/tsci1603913z.

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Time-dependent cloud cavitation around the 2-D Clark-Y hydrofoil was investigated in this paper based on an improved filter based model and a density correction method. The filter-scale in filter based model simulation was discussed and validated according to the grid size. Numerical results show that in the transition from sheet cavitation to cloud cavitation, the sheet cavity grows slowly to the maximum length during the re-entrant jet develops. The mild shedding bubble cluster convects downwards the hydrofoil and continues to grow up after detaching from the suction surface of hydrofoil, and a bubble cluster introduced at the rear part of hydrofoil. While the sheet cavity generates, the bubble cluster breakups.
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45

MATSUDA, Jin-ichi, Kazuo KATO, and Yoshiaki SAITOH. "The Application of a Re-entrant Type Resonant Cavity Applicator to Deep and Concentrated Hyperthermia." Thermal Medicine(Japanese Journal of Hyperthermic Oncology) 4, no. 2 (1988): 111–18. http://dx.doi.org/10.3191/thermalmedicine.4.111.

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46

NAGASAWA, Junichi, Jiro ARAKAWA, YUYA Iseki, Yasuhiro SHINDO, and Kazuo KATO. "2D44 Heating properties of re-entrant type resonant cavity applicator using simple blood vessel model." Proceedings of the Bioengineering Conference Annual Meeting of BED/JSME 2014.26 (2014): 427–28. http://dx.doi.org/10.1299/jsmebio.2014.26.427.

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47

Bansiwal, Ashok, Sushil Raina, K. J. Vinoy, and Subrata Kumar Datta. "A simple method for estimating the quality factor of cylindrical re-entrant cavity of Klystrons." Journal of Electromagnetic Waves and Applications 33, no. 8 (March 18, 2019): 1082–91. http://dx.doi.org/10.1080/09205071.2019.1592710.

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48

Nakayama, Shigeru. "Microwave Sensor of Basis Weight and Moisture Content of Sheet Materials by Re-Entrant Cavity." Japanese Journal of Applied Physics 26, Part 1, No. 11 (November 20, 1987): 1935–36. http://dx.doi.org/10.1143/jjap.26.1935.

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49

TSAI, T. M., and MICHAEL J. MIKSIS. "The effects of surfactant on the dynamics of bubble snap-off." Journal of Fluid Mechanics 337 (April 25, 1997): 381–410. http://dx.doi.org/10.1017/s0022112097004898.

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The effects of an insoluble surfactant on the motion of a drop or bubble as it is driven by a pressure gradient through a capillary tube is investigated numerically. We find that a drop in a straight capillary tube can either approach a steady-state shape or develop a re-entrant cavity at its rear. For a gas bubble moving through a constricted capillary tube, we find that snap-off can occur and surfactants enhance the snap-off process. The effects of the parameters on the dynamics of bubble snap-off are illustrated and discussed.
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50

Wei, Zhihua, Jie Huang, Jing Li, Guoqing Xu, Zongde Ju, Xuyang Liu, and Xingsheng Ni. "A High-Sensitivity Microfluidic Sensor Based on a Substrate Integrated Waveguide Re-Entrant Cavity for Complex Permittivity Measurement of Liquids." Sensors 18, no. 11 (November 16, 2018): 4005. http://dx.doi.org/10.3390/s18114005.

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In this study, a novel non-invasive and contactless microwave sensor using a square substrate integrated waveguide (SIW) re-entrant cavity is proposed for complex permittivity measurement of chemical solutions. The working principle of this sensor is based on cavity perturbation technique, in which the resonant properties of cavity are utilized as signatures to extract the dielectric information of liquid under test (LUT). A winding microfluidic channel is designed and embedded in the gap region of the cavity to obtain a strong interaction between the induced electric field and LUT, thus achieving a high sensitivity. Also, a mathematical predictive model which quantitatively associates the resonant properties of the sensor with the dielectric constant of LUT is developed through numerical analysis. Using this predictive model, quick and accurate extraction of the complex permittivity of LUT can be easily realized. The performance of this sensor is then experimentally validated by four pure chemicals (hexane, ethyl acetate, DMSO and water) together with a set of acetone/water mixtures in various concentrations. Experimental results demonstrate that the designed sensor is capable of characterizing the complex permittivities of various liquids with an accuracy of higher than 96.76% (compared with the theoretical values obtained by Debye relaxation equations), and it is also available for quantifying the concentration ratio of a given binary mixture.
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