Roughness receptivity in swept-wing boundary layers – computations. (1st March 2010)

• Record Type: Journal Article
• Authors: Rhodes, Richard G.; Reed, Helen L.; Saric, William S.; Carpenter, Andrew L.; , Tyler P. Neale
• Is Part Of: International journal of engineering systems modelling and simulation. Volume 2:Number 1/2(2010)
• Page Start: 139
• Page End: 148
• Publication Date: 2010-03-01
• Subjects: roughness receptivity -- swept wings -- 3D boundary layers -- experiments -- laminar flow control -- discrete roughness elements -- crossflow instability -- hotfilm sensors -- disturbance amplitude variations -- disturbance wall shear stress; Engineering systems -- Computer simulation -- Periodicals; Engineering systems -- Mathematical models -- Periodicals; 620.0042
• Languages: English
• ISSNs: 1755-9758

Abstract

The crossflow instability responsible for transition over a swept wing has been found to be ultra-sensitive to micron-sized roughness at the leading edge. Transition-predictive tools are limited because of the lack of models connecting physical roughness characteristics with initial and boundary conditions needed by the computational codes. The Texas A&M Flight Research Lab (FRL) is currently conducting flight tests of a laminar flow 30° swept wing model (SWIFT – swept wing in flight tests) mounted vertically below the port wing hard-point of a Cessna O-2A Skymaster and operated at chord Reynolds numbers on the order of 7.5 million. Various roughness configurations are correlated with local skin-friction measurements downstream. As a companion to the flight experiments, the group has engaged in a computational study aimed at relating roughness features to the resulting initial amplitude of the instability. This will provide a critical connection between stability analysis design tools and transition location prediction.