Abstract
Turbulence modulation in a flow with neutrally suspended particles has been experimentally investigated. The turbulent field generated by an oscillating grid was adopted as a basic turbulent field. Since there is no mean shear flow in it, the steady state can be easily attained. In the present study, the spatial characteristics, such as 1-dimensional wave number spectra and integral-length scales, in multiphase turbulent flows have been examined on the basis of measurements by traversing FLV. The main results are as follows:
When neutrally suspended particles exist in the flow, new eddies whose dimensionless wave number kd/2π is about 0.2 are generated. The eddies seem to be those of wake due to a relative velocity between a particle and ambient fluid because the value of kd/2π corresponds to the Strouhal number St found behind a rigid sphere in an uniform flow. Consequently, a wave number spectrum has a peak around kd/2π=0.2 if a comparably large number of spherical particles are contained in the flow.
