Scaling of pressure spectrum in turbulent boundary layers

1st Multiflow Summer Workshop

Patwardhan, Saurabh S.^1 ; Ramesh, O.N.^1

Department of Aerospace Engineering, Indian Institute of Science, Bangalore, India^1

关键词: Local reynolds stress;    Modulation coefficients;    Pressure fluctuation;    Small scale turbulence;    Stream-wise velocities;    Turbulent boundary layers;    Turbulent kinetic energy;    Zero-pressure gradient turbulent boundary layer;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/506/1/012011/pdf
DOI  :  10.1088/1742-6596/506/1/012011

来源: IOP

【 摘 要 】

Scaling of pressure spectrum in zero-pressure-gradient turbulent boundary layers is discussed. Spatial DNS data of boundary layer at one time instant (Reθ 4500) are used for the analysis. It is observed that in the outer regions the pressure spectra tends towards the -7/3 law predicted by Kolmogorov's theory of small-scale turbulence. The slope in the pressure spectra varies from -1 close to the wall to a value close to -7/3 in the outer region. The streamwise velocity spectra also show a -5/3 trend in the outer region of the flow. The exercise carried out to study the amplitude modulation effect of the large scales on the smaller ones in the near-wall region reveals a strong modulation effect for the streamwise velocity, but not for the pressure fluctuations. The skewness of the pressure follows the same trend as the amplitude modulation coefficient, as is the case for the velocity. In the inner region, pressure spectra were seen to collapse better when normalized with the local Reynolds stress than when scaled with the local turbulent kinetic energy