Downstream Influence Scaling of Turbulent Flow past Expansion Corners

theory, when appropriate allowances are made for the noisy freestream and the nonlinear disturbances not identified by the linear theories. It remains to be determined if the incompatibility of planar boundary-layer instability phenomena with classical linear stability theory is a unique feature of the planar boundary layer or if it is a noisy wind-tunnel characteristic that affects planar boundary layers but not conical boundary layers. Quiet tunnel stability experiments would be very helpful in resolving this planar configuration problem and evaluating other conventional wind-tunnel transition issues.