Tanja Weller

Comparison of direct numerical simulations and particle-image velocimetry data of turbulent channel flow rotating about the streamwise axis

The influence of rotation about the streamwise axis on a turbulent channel flow is discussed by analyzing and comparing numerical and experimental data. The numerical study uses direct numerical simulations (DNS), while the experiments were based on particle-image velocimetry (PIV). The flow properties in the numerical and experimental analyses were maintained as similar as possible. For comparability with data from the literature the nonrotating channel flow at a Reynolds number Reτ=180 serves as a reference problem. Depending on the rotation rate of the channel the development of a secondary flow perpendicular to the main flow has been found in both investigations. The rotation primarily influences those components of the Reynolds shear stresses, which contain the spanwise velocity component. The size of the correlation areas and thus the length scales of the flow increase in all three coordinate directions, leading to longer structures. The increased momentum exchange can be deducted from the behavior ...

DNS of a Turbulent Channel Flow with Streamwise Rotation - Investigation on the Cross Flow Phenomena

Modelling of rotating turbulent flows is a major issue in engineering applications. Intensive research has been dedicated to rotating channel flows in spanwise direction such as by [1], [2] to name only two. In this work a turbulent channel flow rotating about the streamwise direction is presented. The theory is based on the investigations of [4] employing the symmetry group theory. It was found that a cross flow in the spanwise direction is induced. Statistical evaluations have shown that all six components of the Reynolds stress tensor are non zero. A series of direct numerical simulations (DNS) has been conducted both for different rotation rates and different Reynolds numbers. Results of the DNS are presented and discussed.