Готові списки джерел за темами / Depth-induced breaking

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Добірка наукової літератури з теми "Depth-induced breaking"

Автор: Grafiati

Опубліковано: 9 листопада 2022

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Статті в журналах з теми "Depth-induced breaking"

Salmon, J. E., and L. H. Holthuijsen. "Modeling depth-induced wave breaking over complex coastal bathymetries." Coastal Engineering 105 (November 2015): 21–35. http://dx.doi.org/10.1016/j.coastaleng.2015.08.002.

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Salmon, J. E., L. H. Holthuijsen, M. Zijlema, G. Ph van Vledder, and J. D. Pietrzak. "Scaling depth-induced wave-breaking in two-dimensional spectral wave models." Ocean Modelling 87 (March 2015): 30–47. http://dx.doi.org/10.1016/j.ocemod.2014.12.011.

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Smit, Pieter, Marcel Zijlema, and Guus Stelling. "Depth-induced wave breaking in a non-hydrostatic, near-shore wave model." Coastal Engineering 76 (June 2013): 1–16. http://dx.doi.org/10.1016/j.coastaleng.2013.01.008.

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FRUCTUS, DORIAN, MAGDA CARR, JOHN GRUE, ATLE JENSEN, and PETER A. DAVIES. "Shear-induced breaking of large internal solitary waves." Journal of Fluid Mechanics 620 (February 10, 2009): 1–29. http://dx.doi.org/10.1017/s0022112008004898.

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The stability properties of 24 experimentally generated internal solitary waves (ISWs) of extremely large amplitude, all with minimum Richardson number less than 1/4, are investigated. The study is supplemented by fully nonlinear calculations in a three-layer fluid. The waves move along a linearly stratified pycnocline (depth h2) sandwiched between a thin upper layer (depth h1) and a deep lower layer (depth h3), both homogeneous. In particular, the wave-induced velocity profile through the pycnocline is measured by particle image velocimetry (PIV) and obtained in computation. Breaking ISWs were found to have amplitudes (a1) in the range $a_1\,{>}\,2.24\sqrt{h_1h_2}(1+h_2/h_1)$, while stable waves were on or below this limit. Breaking ISWs were investigated for 0.27 < h2/h1 < 1 and 4.14 < h3/(h1 + h2) < 7.14 and stable waves for 0.36 < h2/h1 < 3.67 and 3.22 < h3/(h1 + h2) < 7.25. Kelvin–Helmholtz-like billows were observed in the breaking cases. They had a length of 7.9h2 and a propagation speed 0.09 times the wave speed. These measured values compared well with predicted values from a stability analysis, assuming steady shear flow with U(z) and ρ(z) taken at the wave maximum (U(z) horizontal velocity profile, ρ(z) density along the vertical z). Only unstable modes in waves of sufficient strength have the chance to grow sufficiently fast to develop breaking: the waves that broke had an estimated growth (of unstable modes) more than 3.3–3.7 times than in the strongest stable case. Evaluation of the minimum Richardson number (Rimin, in the pycnocline), the horizontal length of a pocket of possible instability, with wave-induced Ri < 14, (Lx) and the wavelength (λ), showed that all measurements fall within the range Rimin = −0.23Lx/λ + 0.298 ± 0.016 in the (Lx/λ, Rimin)-plane. Breaking ISWs were found for Lx/λ > 0.86 and stable waves for Lx/λ < 0.86. The results show a sort of threshold-like behaviour in terms of Lx/λ. The results demonstrate that the breaking threshold of Lx/λ = 0.86 was sharper than one based on a minimum Richardson number and reveal that the Richardson number was found to become almost antisymmetric across relatively thick pycnoclines, with the minimum occurring towards the top part of the pycnocline.

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Hieu, Phung Dang, and Phan Ngoc Vinh. "A numerical model for simulation of near-shore waves and wave induced currents using the depth-averaged non-hydrostatic shallow water equations with an improvement of wave energy dissipation." Tạp chí Khoa học và Công nghệ biển 20, no. 2 (May 22, 2020): 155–72. http://dx.doi.org/10.15625/1859-3097/20/2/15087.

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This study proposes a numerical model based on the depth-integrated non-hydrostatic shallow water equations with an improvement of wave breaking dissipation. Firstly, studies of parameter sensitivity were carried out using the proposed numerical model for simulation of wave breaking to understand the effects of the parameters of the breaking model on wave height distribution. The simulated results of wave height near the breaking point were very sensitive to the time duration parameter of wave breaking. The best value of the onset breaking parameter is around 0.3 for the non-hydrostatic shallow water model in the simulation of wave breaking. The numerical results agreed well with the published experimental data, which confirmed the applicability of the present model to the simulation of waves in near-shore areas.

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Kuznetsov, Sergey, Yana Saprykina, and Valentina Volkova. "DEPENDENCIES OF BREAKING TYPE, BREAKING CRITERIA AND ENERGY DISSIPATION ON AMPLITUDE-PHASE FREQUENCY STRUCTURE OF WAVES." Coastal Engineering Proceedings, no. 36 (December 30, 2018): 72. http://dx.doi.org/10.9753/icce.v36.papers.72.

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Type of wave breaking - plunging or spilling - depends on symmetry of waves. The spilling waves are asymmetric against horizontal axis and are practically symmetric against vertical axis so the phase shift between first and second nonlinear harmonics (or biphase) is close to zero. The plunging breaking waves have larger asymmetry against vertical axis, (biphase is close to -pi/2), and near symmetric on horizontal axis (close to saw-toothed form). Non-linear wave transformation influences on depth-induced wave breaking. Breaking index depends on relation of wave energy in frequency range of second nonlinear harmonics to wave energy in frequency range of main harmonic and on biphase. The dissipation rate of spilling breaking waves energy quadratically depends on frequency, while in plunging breaking, this dependency is practically linear for all frequencies.

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Chen, Zereng, Qinghe Zhang, Yongsheng Wu, and Chao Ji. "A modified breaker index formula for depth-induced wave breaking in spectral wave models." Ocean Engineering 264 (November 2022): 112527. http://dx.doi.org/10.1016/j.oceaneng.2022.112527.

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Draycott, S., Y. Li, P. K. Stansby, T. A. A. Adcock, and T. S. van den Bremer. "Harmonic-induced wave breaking due to abrupt depth transitions: An experimental and numerical study." Coastal Engineering 171 (January 2022): 104041. http://dx.doi.org/10.1016/j.coastaleng.2021.104041.

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Seyed Alipur, Seyed Ali, Seyed Mostafa Siadatmousavi, and Seyed Masoud Mahmoudof. "Improving the Simulation of Depth-induced Breaking in the Third-Generation Wave Model SWAN." مهندسی دریا 16, no. 31 (April 1, 2020): 53–64. http://dx.doi.org/10.29252/marineeng.16.31.53.

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Deike, Luc, Nick Pizzo, and W. Kendall Melville. "Lagrangian transport by breaking surface waves." Journal of Fluid Mechanics 829 (September 19, 2017): 364–91. http://dx.doi.org/10.1017/jfm.2017.548.

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The Lagrangian transport due to non-breaking and breaking focusing wave packets is examined. We present direct numerical simulations of the two-phase air–water Navier–Stokes equations describing focusing wave packets, investigating the Lagrangian drift by tracking tracer particles in the water before, during and after the breaking event. The net horizontal transport for non-breaking focusing packets is well described by the classical Stokes drift, both at the surface and in the bulk of the fluid, where the e-folding scale of the evanescent vertical profile is given by the characteristic wavenumber. For focusing wave packets that lead to breaking, we observe an added drift that can be ten times larger than the classical Stokes drift for a non-breaking packet at the surface, while the initial depth of the broken fluid scales with the wave height at breaking. We find that the breaking induced Lagrangian transport scales with the breaking strength. A simple scaling argument is proposed to describe this added drift and is found to be consistent with the direct numerical simulations. Applications to upper ocean processes are discussed.

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Більше джерел

Дисертації з теми "Depth-induced breaking"

Pezerat, Marc. "Étude de la dynamique hydro-sédimentaire de la zone pré-littorale." Thesis, La Rochelle, 2022. http://www.theses.fr/2022LAROS010.

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Ces travaux traitent de la dynamique hydro-sédimentaire de la zone pré-littorale en combinant l'exploitation de mesures in situ acquises dans des conditions modérément énergétiques à paroxysmales avec des simulations numériques d'un système de modélisation morphodynamique 3D qui s'appuie sur une approche "force vortex". Nous mettons d’abord en évidence une sous estimation de la hauteur significative des vagues modélisée dans des conditions paroxysmales, associée à une contribution surestimée du terme de dissipation par déferlement bathymétrique. Pour pallier à ce problème, nous introduisons une nouvelle paramétrisation du coefficient de déferlement qui contrôle la saturation des vagues déferlantes dans ces modèles. Nous présentons ensuite une étude qui porte sur la dynamique hydro-sédimentaire de la zone pré-littorale interne. Nous étudions la distribution spatiale et les mécanismes d'entraînement de la circulation transversale induite par les vagues en s'appuyant sur une caractérisation spatiale des processus de dissipation et nous analysons la dynamique du transport en suspension. Le transport opéré par le courant moyen apparaît dominant et on observe, en particulier, un transport net orienté vers le large associé au courant de retour forcé par les vagues. Enfin, nous présentons une dernière étude qui porte sur la dynamique hydro-sédimentaire et les évolutions morphologiques saisonnières à annuelles de la zone pré-littorale externe au niveau d’une concession d'extraction de granulats marins. Nous mettons notamment en évidence une dynamique de comblement des souilles d'extraction qui se produit essentiellement sous des conditions incidentes fortement énergétiques
This work deals with the hydro-sedimentary dynamics of the shoreface by combining the exploitation of in situ measurements acquired under moderately energetic to paroxysmal conditions with numerical simulations of a 3D morphodynamic modelling system, where short waves and mean currents are coupled based on a vortex force formalism. We first highlight an underestimation of the significant wave height modelled in paroxysmal conditions, associated with an overestimated contribution of the depth-induced breaking dissipation term. To overcome this problem, we introduce a new parameterization of the breaking coefficient that controls the saturation of breaking waves in these models. We then present a study of the hydro-sedimentary dynamics of the upper shoreface. We examine the spatial distribution and driving mechanisms of the wave-induced cross-shore current based on the relative contribution of the different dissipation processes. The analysis of the dynamics of suspended sediment transport reveals that it is mainly operated by the mean current, which explains its net seaward direction associated with the wave-driven return current. Finally, we present a last study on the hydro-sedimentary dynamics and the seasonal to annual morphological evolutions of the lower shoreface nearby a sandy granulate extraction area. In particular, we highlight the filling dynamics of the extraction pits, which occur mainly under high-wave energy incident conditions

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Тези доповідей конференцій з теми "Depth-induced breaking"

LIM, SIN HWEI LYDIA, and ENG SOON CHAN. "SURF ZONE WAVE MODELING: IMPROVEMENT OF DISSIPATION BY DEPTH-INDUCED BREAKING IN SWAN AND APPLICATION IN MALACCA STRAITS." In Proceedings of the 29th International Conference. World Scientific Publishing Company, 2005. http://dx.doi.org/10.1142/9789812701916_0035.

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Kolokythas, Gerasimos A., and Athanassios A. Dimas. "Numerical Simulation of Oblique Wave Breaking and Wave-Induced Currents in the Surf Zone." In ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-24125.

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In the present study, the three-dimensional, incompressible, turbulent, free-surface flow, developing by the propagation and breaking of nonlinear gravity waves over a constant-slope beach, is numerically simulated. The main objective is to investigate the flow structure in the surf zone as a result of the interaction between the longshore and the undertow current, induced by spilling wave breaking, oblique to the shoreline. The simulations are performed employing the so-called large-wave simulation (LWS) method coupled with a numerical solver for the Navier-Stokes equations. According to the employed LWS methodology, large velocity and free-surface scales are fully resolved, while the effect of subgrid scales is modeled by eddy-viscosity stresses, similar to large-eddy simulation (LES) methodology. In order to validate our model, the case of incoming Stokes waves with wavelength to inflow depth ratio λ/dI ≈ 6.6 and wave steepness H/λ ≈ 0.025, propagating normal to the shore over a bed of constant slope 1/35, is investigated. Our results are compared to published experimental measurements, and it is found that the LWS model predicts adequately the wave breaking parameters — breaking height and depth — and the distribution of the undertow current in the surf zone. Two cases of oblique breaking waves, with inflow angles φI = 20° and 30°, and all other parameters identical to that of the validation case, are considered. The gradual breaking of the refracted waves is captured, as well as the three-dimensional structure of the flow in the surf zone. LWS-predicted profiles of the undertow and the longshore current at several positions in the surf zone, are presented. It is indicated that the undertow prevails in the outer surf zone, while the longshore current becomes stronger in the inner surf zone and reaches its maximum magnitude close to the shore.

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Belibassakis, K. A., Th P. Gerostathis, and G. A. Athanassoulis. "A Coupled-Mode Technique for the Prediction of Wave-Induced Set-Up and Mean Flow in Variable Bathymetry Domains." In ASME 2007 26th International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2007. http://dx.doi.org/10.1115/omae2007-29365.

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In the present work, a complete, phase-resolving wave model is coupled with an iterative solver of the mean-flow equations in intermediate and shallow water depth, permitting an accurate calculation of wave set-up and wave-induced current in intermediate and shallow water environment with possibly steep bathymetric variations. The wave model is based on the consistent coupled-mode system of equations, developed by Athanassoulis & Belibassakis (1999) for the propagation of water waves in variable bathymetry regions. This model improves the predictions of the mild-slope equation, permitting the treatment of wave propagation in regions with steep bottom slope and/or large curvature. In addition, it supports the consistent calculation of wave velocity up to and including the bottom boundary. The above wave model has been further extended to include the effects of bottom friction and wave breaking, which are important factors for the calculation of radiation stresses on decreasing depth. The latter have been used as forcing terms to the mean flow equations in order to predict wave-induced set up and mean flow in open and closed domains. Numerical results obtained by the present model are presented and compared with predictions obtained by the mild-slope approximation (Massel & Gourlay 2000), and experimental data (Gourlay 1996).

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Belibassakis, K. A. "Infragravity Waves Induced by Short-Wave Groups in Coastal Regions Characterized by General Bottom Topography." In ASME 2011 30th International Conference on Ocean, Offshore and Arctic Engineering. ASMEDC, 2011. http://dx.doi.org/10.1115/omae2011-49280.

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The free long-wave generation by short-wave groups over a sloping bottom is studied both experimentally and theoretically by various authors showing important results concerning the modelling of energy transfer from the short waves to subharmonics. In the present work, the coupled-mode model developed by Athanassoulis & Belibassakis (1999) for the propagation of water waves over variable bathymetry regions, as generalized to include dissipation due to bottom friction and breaking effects, is applied to calculate the spatial evolution of short-wave groups propagating over a shoaling area, characterized by general bottom topography. Following Scha¨ffer (1993), the present model is appropriately modified in the surf zone in order to destroy the short-wave modulation, keeping the wave height decay in proportion to the local water-depth, and is then used to calculate radiation stresses associated with shoaling and breaking of short-wave groups in the area of general bathymetry and in the surf zone. Subsequently, the system of long wave equations, corresponding to zero (set-down/set-up) and first few harmonics, forced by the radiation stresses, is numerically solved. Results are presented showing that the present model provides reasonable predictions, supporting the study of infragravity waves induced by shortwave groups and their effects on harbors and mooring systems of large vessel operating in nearshore/coastal regions.

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Valentine, Daniel T., and Jannette B. Frandsen. "Nonlinear Free-Surface and Viscous-Internal Sloshing in 2-D Numerical Wave Tanks." In ASME 2003 22nd International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2003. http://dx.doi.org/10.1115/omae2003-37321.

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This paper examines free-surface and internal-pycnocline sloshing motions in 2-D numerical wave tanks subjected to horizontal base excitation. In all of the cases studied, the rectangular tank of liquid has a width-to-depth ratio of 2. The first set of results are based on an inviscid, fully nonlinear finite difference free-surface model. The model equations are mapped from the physical domain onto a rectangular domain. Case studies at and off resonance are presented illustrating when linear theory is inadequate. The next set of results are concerned with analyzing internal waves induced by sloshing a density-stratified liquid. Nonlinear, viscous flow equations are solved. The influence of the side-wall boundary layers on sloshing motions as well as the onset of internal breaking of the primary sloshing mode are discussed. The frequencies that characterize the motion of internal waves are also reported.

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Downing, J., and A. Hook. "A Practical Ultrasonic Inspection Method for Detecting and Characterising Defects Found Within Composite Repairs." In 14th International Naval Engineering Conference and Exhibition. IMarEST, 2018. http://dx.doi.org/10.24868/issn.2515-818x.2018.013.

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Two steel substrate test panels were developed to represent common plate thicknesses found on naval vessels and scanned using the Babcock developed ultrasonic technique. One sample comprised of a series of slotted surface breaking flaws of varying widths and through thicknesses to represent fracturing/cracking. The inspection method detected simulated cracking to a depth of 2mm and 0.5mm in width. The second sample included numerous loss of wall thickness areas of varying diameters and through thicknesses, with the smallest detectable loss of wall thickness being 0.1mm at a 15mm diameter. After proving confidence in detection, there was a need to characterise flaws to provide support and ascertain a repair action. Samples were produced that were subjected to either impact or heat exposure to induce realistic representative damage. The practical ultrasonic method was successfully used to independently characterise between the samples, with induced de-laminations caused by blisters, and multi layered matrix cracking caused by varying levels of projectile impacts, due to their unique morphology.

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Koutrouveli, Theofano I., and Athanassios A. Dimas. "Numerical Simulation of Wave Propagation Over Submerged Composite Breakwaters Using the Immersed Boundary Method." In ASME 2014 33rd International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2014. http://dx.doi.org/10.1115/omae2014-24055.

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The two-dimensional flow induced by waves over submerged breakwaters of two different shapes is studied by means of a two-phase (water and air) Navier-Stokes equations solver. A time-splitting method is used for the temporal discretization, while the spatial discretization is based on the use of finite differences in a Cartesian staggered grid. The implementation of the boundary conditions at solid surfaces, as well as the treatment of the free surface is performed using the immersed boundary method where the breakwater, the seabed and the free surface are boundaries immersed in the numerical grid. The numerical model was applied on the propagation and breaking over a constant slope beach, as well as on the propagation and nonlinear transformation of waves over two types of submerged breakwaters, i.e., trapezoidal and composite (with berm in the up-slope side). The results of the numerical model reveal that the presence of the berm reduces the transmission coefficient and this reduction increases with the decrease of the berm depth of submergence.

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Eswaran, M., та Ujjwal K. Saha. "Waves Simulation in an Excited Cylindrical Tank Using σ-Transformation". У ASME 2010 International Mechanical Engineering Congress and Exposition. ASMEDC, 2010. http://dx.doi.org/10.1115/imece2010-39752.

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Free surface motions of the liquid in partially filled tanks under gravity are of practical significance particularly in marine and road transportation applications. For this reason, liquid sloshing has always been a research subject attracting great concern during the last several decades. Numerical experiments of sloshing wave motion are undertaken in a 2-D tank which is moved horizontally. Results of liquid sloshing induced by sinusoidal base excitations are presented for small to steep non-breaking waves. The numerical model is valid for any water depth except for small depth when viscous effects would become important. Solutions are limited to steep non-overturning waves. In this paper, the semi-circular domain with time-varying fluid surface was mapped onto a rectangular domain by the σ-transformation. Based on the inviscid flow equations, a fully non-linear finite difference model has been developed. The simulations are limited to a half-filled container. The liquid free surface elevation and wave phase-plane diagram have been plotted for different tank excitation frequency. It has been observed that while increasing the tank frequency, the liquid wave height in the tank changes according to the system natural frequency. Finally, the proposed computational scheme has been applied to a real engineering problem to capture the irregular behavior of liquid free surface inside the tank. For this, acceleration-time history of EW and NS components of the EL-Centro earthquake, California has been studied and analyzed.

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Frandsen, Jannette B. "Tank Sloshing Interaction With Elastic Support Structure." In ASME 2004 23rd International Conference on Offshore Mechanics and Arctic Engineering. ASMEDC, 2004. http://dx.doi.org/10.1115/omae2004-51371.

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A fully nonlinear 2-D σ-transformed finite difference solver has been developed based on inviscid flow equations in rectangular tanks. The fluid equations are coupled to an elastic support structure. Sloshing motion are simulated during structural vibration cycles at and outside resonance. The wave tank acts as a Tuned Liquid Damper (TLD). The TLD response is highly nonlinear due to the liquid sloshing. The solver is valid at any water depth except for small depth when shallow water waves and viscous effects would become important. Results of liquid sloshing induced by horizontal base excitations are presented for small to steep non-breaking waves. The effectiveness of the TLD is discussed through predictions of coupling frequencies of the tank-structural system for different tank sizes and mass ratios between fluid and structure. Good agreement is achieved between numerical model and first-order theory. It was found that the system response is extremely sensitive to small changes in forcing frequency. Furthermore, the solver removes the need for free-surface smoothing for the cases considered herein. The numerical model provides a quick and accurate way of determining system eigenfrequencies which can be hard to identify and interpret in physical experiments. Therefore the numerical solver could serve as a valuable guidance to physical experiments. The present studies can easily be expanded to include multiple wave tanks to investigate tank interaction effects, and thus cover suppression of a wider range of frequencies.

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San Andre´s, Luis, and Adolfo Delgado. "A Novel Bulk-Flow Model for Improved Predictions of Force Coefficients in Grooved Oil Seals Operating Eccentrically." In ASME 2011 Turbo Expo: Turbine Technical Conference and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/gt2011-45274.

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Oil seals in centrifugal compressors reduce leakage of the process gas into the support bearings and ambient. Under certain operating conditions of speed and pressure, oil seals lock, becoming a source of hydrodynamic instability due to excessively large cross coupled stiffness coefficients. It is a common practice to machine circumferential grooves, breaking the seal land, to isolate shear flow induced film pressures in contiguous lands, and hence reducing the seal cross coupled stiffnesses. Published tests results for oil seal rings shows that an inner land groove, shallow or deep, does not actually reduce the cross-stiffnesses as much as conventional models predict. In addition, the tested grooved oil seals evidenced large added mass coefficients; while predictive models, based on classical lubrication theory, neglect fluid inertia effects. This paper introduces a bulk-flow model for groove oil seals operating eccentrically and its solution via the finite element method. The analysis relies on an effective groove depth, different from the physical depth, which delimits the upper boundary for the squeeze film flow. Predictions of rotordynamic force coefficients are compared to published experimental force coefficients for a smooth land seal and a seal with a single inner groove with depth equaling 15 times the land clearance. The test data represent operation at 10 krpm and 70 bar supply pressure, and four journal eccentricity ratios (e/c = 0, 0.3, 0.5, 0.7). Predictions from the current model agree with the test data for operation at the lowest eccentricities (e/c = 0.3); discrepancies increasing at larger journal eccentricities. The new flow model is a significant improvement towards the accurate estimation of grooved seal cross-coupled stiffnesses and added mass coefficients; the later previously ignored or largely under predicted.

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