Excitation of a Turbulent Boundary Layer by Pulses.
JOHNS HOPKINS UNIV BALTIMORE MD DEPT OF MECHANICS
Pagination or Media Count:
A low duty cycle periodically pulsed jet was injected into a zero pressure gradient turbulent boundary layer through a small hole in the wall in order to simulate or stimulate the ejections of turbulent bursts from the active region near the viscous sublayer. The method of periodic sampling, in synchronism with the pulsed jet action was employed to detect the periodic part of the flow field disturbed by the injected jet. The trajectory through the turbulent boundary layer, the transporting velocity and the decay of the resulting disturbance were all measured in detail. A fewer exploratory runs were made with injections from very large diameter orifice in order to shoot the disturbance through the entire boundary layer thickness. In that case, higher Reynolds stress value was observed in the disturbed region when comparing with the value in a normal turbulent boundary layer. Author
- Fluid Mechanics