Verification and validation of large eddy simulation of cavitating flow in Venturi

  Objective  The adaptability of the accuracy of finite space cavitation flow described by the verification and validation (V&V) method needs to be analyzed quantitatively. To this end, flow under different cavitation numbers in a Venturi tube is subject to large eddy simulation (LES) to implement the V&V method, thereby expanding the application scope of verification and methods.

  Methods  First, the LES and Zwart-Gerber-Belamri (ZGB) cavitation model are used to simulate the flow in the Venturi tube under different cavitation numbers. The accuracy orders and numerical benchmarks of the pressure ratio and pressure coefficient under different working conditions are then calculated using the five-equation V&V method, and the verification uncertainties are calculated. Finally, the validation uncertainties are calculated and compared with the comparison error of the simulation values and experimental results.

  Results  Under the three cavitation numbers, the verification uncertainties of the pressure ratios are small, and the pressure ratios are validated at the uncertainty levels. When the cavitation number is σ=0.263 at x/D_th=9 and x/D_th=13, the verification uncertainties of the pressure coefficients are high, and the pressure coefficients are not validated. The verification uncertainties of the pressure coefficients at other monitoring points and working conditions are small, and the pressure coefficients are validated.

  Conclusions  The five-equation V&V method can smoothly reflect the error of the LES of Venturi flow, but the consumption is high, and the V&V method for the LES of internal cavitation flow in finite space requires further improvement.