Simulation of Sheet and Cloud Cavitation with Homogenous Transport Models

Abstract

This paper introduces the results of correlated numerical models study carried out to analyse cavitating flows. The flow field of steady attached sheet cavitation and the case of unsteady cavitation behaviour with quasi-periodic fluctuations is analysed with different homogenous cavitation transport models. Three models in form of additional transport equations for water volume fraction are combined with the RANS (Reynolds Averaged Navier-Stokes) equations and calibrated for the cavitating flow around the NACA66 (MOD) hydrofoil by means of an optimisation strategy. In the second stage, the optimised models are applied to the case of internal unsteady cavitating flow in Venturi type section.The results obtained using calibrated models are very close to each other, and agree well with the available experimental data, indicating that the optimisation process is recommended as a general -first step tool for mathematical models validation.

Spectral Analysis of Pressure, Noise and Vibration Velocity Measurement in Cavitation

“…The deviation between the pressure drop and the measurement for the non-cavitation area ranged from 0 to 5 %, in the cavitation area the pressure drop deviation was up to 65 %. Therefore, it was necessary to use the cavitation Schnerr Sauer non-stationary model with a time step of 10 -5 s in the area of cavitation flow due to the evaluation of the results by spectral analysis [14], [16], see Fig.14., green line. The deviation was up to 15 %.…”

Numerical analysis of the NiTi solidification process influence of thermal conductivity

“…With each grid refinement the number of elements in a particular direction was doubled and the minimum element size was halved. Such a procedure is useful (and encountered in many numerical studies [11][12][13]) for applying the Richardson's extrapolation technique, which is a method for obtaining a higher-order estimate of the flow value (value at infinite grid) from a series of lower-order discrete values.…”

The Experimental Analysis of Cavitating Structure Fluctuations and Pressure Pulsations in the Cavitation Station

“…Many numerical and experimental studies on cavitating flows have been performed. The numerical studies, performed nowdays mainly focus either on mathematical and physical model development [1], its optimization [2] or on cavitation erosion prediction [3]. The experimental studies have longer history.…”