The present experimental work investigates the evolution and transitional attributes of the geometry-induced separated shear layer (SSL) formed over an anisotropic or three-dimensional irregular rough surface – generated by sandblasting process. Emphasis is placed on the spanwise-vorticity field, thereby exploring the active region of SSL, referred to as the active shear layer, and correlating its topological changes with various stages of transition. In addition, the effect of surface roughness on the onset of shear layer roll-up and nonlinear breakdown to turbulence is examined. In this context, velocity measurements are carried out over the smooth ( Case-I ) and rough ( Case-II ) surfaces, using a single-wire hotwire anemometer. The freestream is set at a low Reynolds number, Re t = 30,000, based on model thickness and inlet velocity, with a turbulence intensity, Tu ≈ 0.8%. The rectification errors and scatter in the measured data are tackled using the modified tanh expression
📖 افتح في inklap 🔗 DOI 📮 اطلب بحثاً