Some measurements of the distortion of turbulence approaching a two-dimensional bluff body

Abstract

This paper describes an experimental study of the distortion of grid-generated turbulence as it approaches the stagnation region of a two-dimensional bluff body. When Lx/D [Gt ] 1, where Lx, is the scale of turbulence and D is a typical body dimension, along the mean stagnation streamline will amplify because of vortex stretching. When Lx/D = O(1) there is found to be a combination of these effects with attenuation of energy at low wavenumbers and amplification at high wavenumbers. Measurements of the pressure fluctuations at the stagnation point show that at low wavenumbers the level of the pressure fluctuations can be predicted by a direct application of Bernoulli's equation.