Influences of freestream turbulence and wake on flow near the stagnation region

Influence of irrotational velocity fluctuation induced by the wake in the region upstream of the bluff bodies was investigated firstly. It is found that this type of fluctuation damps as flow approaches the stagnation region. Effects due to a given upstream disturbance whose length scale is susceptible to be amplified in the stagnation region were studied secondly for two-dimensional and axisymmetric bluff bodies. One of the major findings is that amplification of turbulence intensity in the stagnation region for a two-dimensional bluff body is much more significant than that for the axisymmetric one.