Excitation of a Turbulent Boundary Layer by Pulses.
Abstract
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)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1972
- Accession Number
- AD0742450
Entities
People
- Hajime Fujita
- Leslie S. G. Kovasznay
Organizations
- Johns Hopkins University