Parametric PSE studies on distributed roughness laminar flow control

Non-linear stability analysis tools are used to investigate the development of Saric's Distributed Roughness flow control mechanism as Reynolds number and pressure gradient are varied. Amplitude plots and flow visualization provide complementary information about the flow mechanism but secondary stability analyses are required to predict with confidence the effectiveness of a particular roughness distribution. Anticipated sensitivity to the choice of roughness spacing has not been confirmed by the analysis, suggesting that the linear N-factor development may not be that crucial to the selection of the control mode. Work is still required to bring the tool set up to the standard required for design.