DOI: 10.1615/ICHMT.2006.TurbulHeatMassTransf
ISBN Print: 978-1-56700-229-4
ISSN: 2377-2816
Effects of Periodic Excitation on the Characteristics of a Turbulent Boundary Layer
ABSTRACT
This contribution summarizes the investigations of two flat plate experiments in a water tunnel which deal with the dynamic response and the characteristics of a turbulent boundary layer in interaction with coherent structures induced by dynamic vortex generator jets. The results show that the characteristics of the turbulent fluctuations are nearly unaffected by the flow control process. This allows a separation of scales for physical interpretation and numerical simulation. Secondly, the initial blowing produces an increasing mixing force compared to the steady blowing case, which is even present at high duty-cycles. It is independent of the duty-cycle but varies with the blowing ratio. By considering decay and rebirth of the dynamic vortex structures a new estimation of an optimal frequency for this flow control strategy can be established.