Turbulence and Shear Flow Phenomena -1 First International Symposium

ISBN Print: 1-56700-135-1

DIRECT NUMERICAL SIMULATION ON LAMINARIZATION OF TURBULENT FORCED GAS FLOWS IN CIRCULAR TUBES WITH STRONG HEATING

Résumé

A direct numerical simulation (DNS) with turbulent transport of a variable property fluid has been carried out to grasp and understand the laminarization phenomena caused by strong heating. In this study, the inlet Reynolds number based on a bulk velocity and a pipe diameter was set to be constant at Re=4300. The temperature distribution taken from the experiments by Shehata and McEligot (1998) was applied to the wall as a thermal boundary condition. The number of computational nodes used in this study was 768 × 64 × 128 in the z-, r- and ø- directions, respectively. The turbulent quantities such as the mean flow, temperature fluctuations, turbulent stresses and the turbulent statistics were obtained via DNS. The turbulent drag decreases along the streamwise direction. The cause of this reduction can be considered that the fluid behavior changes drastically in the near wall region due to strong heating.