Numerical simulation of unsteady three-dimensional sheet cavitation

Koop, Arjen

doi:10.3990/1.9789036527019

Cited by 27 publications

(68 citation statements)

References 121 publications

(215 reference statements)

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“…Its accuracy in terms of cavity extents and unsteady behaviour has been demonstrated in previously reported numerical investigations [27,28,29]. Moreover, the model is not dependent on any empirical coefficients, per se, although relies on the choice of the water quality properties, namely nuclei density, n 0 , and mean nuclei radius, R 0 .…”

Section: Cavitation Modellingmentioning

confidence: 74%

Characterisation of sheet cavity noise of a hydrofoil using the Ffowcs Williams–Hawkings acoustic analogy

2016

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Concerns about pollution of the marine environment with ship-induced noise and the scarcity of available numerical methods have recently stimulated significant amounts of research in hydroacoustic modelling. In this work, Large Eddy Simulation (LES) is used with Schnerr-Sauer mass-transfer cavitation model and a porous Ffowcs WilliamsHawkings (FW-H) acoustic analogy in order to simulate sheet cavitation on a NACA0009 hydrofoil. The aim is to investigate how well the proposed method captures the dominant noise sources associated with periodic sheet cavitation. The study further focuses on practical aspects, such as the importance of the non-linear FW-H term and convergence of the acoustic solution depending on the choice of the integration surface. This is done by correlating the radiated noise with integral and local flow quantities, such as cavity volume, lift coefficient and local vapour content. A key finding of the study is that the simulation framework is capable of correctly capturing the monopole nature of the sound generated by an oscillating cavity sheet. Results indicate that the numerical method is incapable of accurately resolving the flow during the final collapse stages of smaller cavity clouds, mainly due to mesh density limitations and the use of an incompressible flow assumption. Lack of small-scale bubble structures also causes the high-frequency range of the noise spectra to be under-predicted. Despite certain limitations the presented method offers a significant insight into the nature of cavitation-dominated noise and allows for some of the dominant sound generating mechanisms to be categorised.

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Section: Cavitation Modellingmentioning

confidence: 74%

Characterisation of sheet cavity noise of a hydrofoil using the Ffowcs Williams–Hawkings acoustic analogy

2016

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“…Finally, the third thermodynamic model which has been utilized, is a more sophisticated extension of the previous barotropic model, since the saturation properties depend on temperature (Koop, 2008;Schmidt et al, 2006). In this case, the modified Tait equation is used for the liquid, the ideal gas EoS for the vapour and the Wallis formula for the mixture.…”

Section: C Homogeneous Equilibrium Mixture With Temperature Effectsmentioning

confidence: 99%

Numerical investigation of bubble dynamics using tabulated data

Kyriazis

Koukouvinis

Gavaises

2017

International Journal of Multiphase Flow

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An explicit density-based solver of the compressible Euler equations suitable for cavitation simulations is presented, using the full Helmholtz energy Equation of State (EoS) for n-Dodecane. Tabulated data are derived from this EoS in order to calculate the thermodynamic properties of the liquid, vapour and mixture composition during cavitation. For determining thermodynamic properties from the conservative variable set, bilinear interpolation is employed; this results to significantly reduced computational cost despite the complex thermodynamics model incorporated. The latter is able to predict the temperature variation of both the liquid and the vapour phases. The methodology uses a Mach number consistent numerical flux, suitable for subsonic up to supersonic flow conditions. Finite volume discretization is employed in conjunction with a second order Runge-Kutta time integration scheme. The numerical method is validated against the Riemann problem, comparing it with the exact solution which has been derived in the present work for an arbitrary EoS. Further validation is performed against the well-known Rayleigh collapse of a pure vapour bubble. It is then used for the simulation of a 2-D axisymmetric n-Dodecane vapour bubble collapsing in the proximity of a flat wall placed at different locations from the centre of the bubble. The predictive capability of the incorporated Helmholtz EoS is assessed against the widely used barotropic EoS and the non-isothermal Homogeneous Equilibrium Mixture (HEM).

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“…Many approaches, for the simulation of the cavitating flow, have been established during the recent years and a great number of mathematical formulations have received increasing attention, particularly the homogeneous flow models (Sauer and Schnerr 2000;Yuan, Sauer, and Schnerr 2001;Kubota, Kato, and Yamaguchi 1992;Koop 2008;Kozubková, Rautová, and Bojko 2012), (Zwart, Gerber, and Belamri 2004) and (Kanfoudi and Zgolli 2011;Kanfoudi and Zgolli 2011Kanfoudi, Lamloumi, and Zgolli 2012, 2014Kanfoudi 2015). This technique is commonly divided into two types based on how to find out the mixture density as the Barotropic equation models (BEM) and the Transport equation based models (TEM).…”

Section: Introductionmentioning

confidence: 99%

Numerical Flow Simulation and Cavitation Prediction in a Centrifugal Pump using an SST-SAS Turbulence Model

Ennouri

Kanfoudi

Taher

et al. 2019

JAFM

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The paper handles the subject of the modelling and simulation of the flow inside a centrifugal pump through non-cavitating and cavitating conditions. Operating under cavitation state is so perilous to a pump and can considerably reduce its lifetime service. Hence, to provide highly reliable pumps, it is essential to comprehend the inner flow of pumps. The investigated centrifugal pump comprises five backward curved-bladed impeller running at 900 rpm. The modelling process started with an unsteady numerical analysis under non-cavitating conditions to validate the numerical model and the solver comparing with the available testing data. Due to high Reynolds numbers, turbulence effects have been taken into account by unsteady RANS methods using an SST-SAS turbulence model. The obtained pump performances were numerically compared with the experimental ones, and the outcome shows an acceptable agreement between both. The temporal distribution of the internal flow parameters such as pressure and velocity was then studied. Furthermore, basic investigations of cavitating flow around 3D NACA66-MOD profile using a recently developed and validate cavitation model was established. The verification of the numerical simulation validity was based on comparing calculated and experimental results and presented good agreement. Finally, a 3D simulation of the inception of the cavitating pocket inside the centrifugal pump is performed to analyze the impact of the cavitation in the decrease of the head and efficiency.

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Numerical simulation of unsteady three-dimensional sheet cavitation

Cited by 27 publications

References 121 publications

Characterisation of sheet cavity noise of a hydrofoil using the Ffowcs Williams–Hawkings acoustic analogy

Characterisation of sheet cavity noise of a hydrofoil using the Ffowcs Williams–Hawkings acoustic analogy

Numerical investigation of bubble dynamics using tabulated data

Numerical Flow Simulation and Cavitation Prediction in a Centrifugal Pump using an SST-SAS Turbulence Model

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