透风型挡风板不同孔隙度大小防风特性的二维数值模拟

Numerical Simulation of Wind Characteristics of the Windshield under Different Sizes of the Porosity

摘要: 本文通过建立二维非定常不可压N-S方程，采用变分多尺度方法对N-S方程进行求解并应用freefem软件对不同孔隙度，不同孔径的透风型挡风板在给定风场进行数值模拟。研究了不同孔隙度下，不同孔径透风型挡风板与不设挡风板及不透型挡风板对风场的影响。结果表明，挡风板具有较好的防风特性，适当孔隙度的透风型挡风板较不透型防风特性好。同时不同孔隙度挡风板对风场影响差异明显，同时相同孔隙度不同孔径挡风板也有较明显差异。在本实验意义下，孔隙度为20%孔径为0.5 cm，高度为50 cm挡风板具有较好的防风特性，在高200 cm，长为500 cm的风场中可以形成198 cm左右的板后涡流长度，形成涡流长度明显长于其他透风型挡风板。

Abstract: Through the establishment of two-dimensional incompressible unsteady flow N-S equation, we solve the N-S equation with the use of variational multiscale methods, make numerical simulation of the wind field for different porosities and aperture ventilated wind screen and study the influence of ventilated wind screen under different porosities and aperture and non-ventilated wind screen on wind field. The results show that the wind screen has great wind resistance characteristics and the wind resistance effect of ventilated wind screen with appropriate porosity is better than that of non-ventilated wind screen. At the same time, the influences of wind screen with different porosities are significantly different and the wind screens with the same porosity but different apertures also have obvious differences. Under this experiment, the porosity is 20% while the aperture is 0.5 cm and the height is 50cm. The wind screen has great wind resistance charac-teristics, forming about 198 cm posterior vortex length in the wind field with the height of 200 cm and the length of 500cm. The vortex length is significantly longer than that of other ventilated wind screen.