Concave-wall turbulent boundary layers without and with free-stream turbulence

Direct numerical simulations are performed to contrast turbulent boundary layers over a concave wall without and with free-stream turbulence. Adverse pressure gradient near the onset of curvature leads sharp decrease in skin friction intermittent separation. The presence turbulence reduces probability reverse flow, accelerates recovery layer downstream zero-pressure region, sustained appreciable increase friction. forcing also promotes amplification coherent G\"ortler structures logarithmic curved-wall layer. Statistically, spanwise wall-normal Reynolds stresses intensify radial distance between their peaks increases as expand. shear stress coefficient when flat-plate is exposed In addition, more energetic roll motions forced flow promote mixing boundary-layer fluids, where former seen often deep within buffer