Structure of Grid Turbulence through a Heated Screen

Abstract

Measurements of mean values and turbulent intensities of velocity and temperature fluctuations of grid turbulence have been made in a developing region just after an electrically heated screen. The air velocity is set as 1m/s. The electric current to the screen is adjusted to be the downstream temperature (Ta) 32°C, 100°C or 150°C. Hot-wire anemometry with compensation for temperature variation is used to measure velocity with temperature variation. In a developing region, both velocity and temperature distributions become non-uniform at a point just downstream of the heated screen. The distributions recover gradually to the uniform condition in a downstream region. Turbulent energy dissipates with the distance from the heated screen. The dissipation rate is decreased with increasing air temperature.