图书馆订阅: Guest
TSFP DL Home 旧刊 执委

TURBULENCE STRUCTURE LEADING TO UNSTEADY UPSTREAM SEPARATION IN COUETTE FLOW WITH FORWARD-FACING STEP

Yohei Morinishi
Graduate School of Engineering Nagoya Institute of Technology Gokiso-cho, Showa-ku, Nagoya, 466-8555, Japan

Shohei Kubota
Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya, 466-8555, Japan

Shinji Tamano
Graduate School of Engineering, Nagoya Institute of Technology Gokiso-cho, Showa-ku, Nagoya, 466-8555, Japan

Toru Yamada
Department of Energy Sciences, Lund University, SE-22100, Lund, Sweden; Graduate School of Engineering Nagoya Institute of Technology Gokiso-cho, Showa-ku, Nagoya, 466-8555, Japan

Abstract

The turbulence structure leading to unsteady upstream separation in a Couette flow with a forard-facing step is studied using PIV and DNS. The counter-gradient diffusion phenomenon (CDP) of the Reynolds stress appeared near the downstream separation is considered by means of conditional averaging based on the reverse flow area in the upstream separation. The negative production of the turbulence kinetic energy which is a quantitative measure of the CDP is mainly produced when the upstream separation has open form.