We did some analysis here for hypersonic flow in a scramjet intake, specially considering the separation of the BL due to shock wave/boundary-layer interaction (SWBLI). It may not correlate directly to the flow speeds you are dealing with, but what we have observed, and it agrees with theory and data in the literature, is that increasing the free stream turbulence intensity limits the propensity of the BL to separate. At Tu = 10%, no separation was present at all. So, yes, the effects of the bubble diminish and even disappear at high enough turbulences.
Although I have mostly focused on flow control, some of our work has investigated this implicitly. In general, the increased freestream turbulence causes the transition point in the shear layer to move closer and closer to the separation point. Depending on the severity of the separation this may result in reattachment and/or the formation of a laminar separation bubble. It also results in a more rapid spreading of the shear layer.
Read "Wall shear stress modulation in a turbulent flow Subjected to imposed unsteadiness with adverse pressure gradient" of Tardu and Maestri, the data are trustworthy!
Read the last paragraph of the conclusions, perhaps there is a possible correlation!
Mr Stuart, and Rogerio, considering the case of Airfoils , data from different wind tunnels with different turbulence levels vary specially in drag forces. Are those results true representative of the airfoil behavior in free air. The effects of laminar separation bubble might diminish at higher turbulence !!
We did some analysis here for hypersonic flow in a scramjet intake, specially considering the separation of the BL due to shock wave/boundary-layer interaction (SWBLI). It may not correlate directly to the flow speeds you are dealing with, but what we have observed, and it agrees with theory and data in the literature, is that increasing the free stream turbulence intensity limits the propensity of the BL to separate. At Tu = 10%, no separation was present at all. So, yes, the effects of the bubble diminish and even disappear at high enough turbulences.
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