Effect of Surface Roughness Geometry on Boundary-Layer Transition and Far-Field Noise

Surface roughness elements are often used to force laminar to turbulent transition in aerodynamic and aeroacoustic wind-tunnel experiments. The statistical features and spectral content of the pressure fluctuations in the resulting turbulent boundary layer at the trailing edge can affect far-field noise. To elucidate this dependence, boundary...

Boundary layer transition induced by distributed roughness array

The effects of a finite, spanwise-periodic array of cylindrical roughness elements on boundary layer transition over a NACA 0012 airfoil are investigated at a chord-based Reynolds number of 1.44×10⁵ by using hotwire anemometry and infrared thermography. Both the number and the spanwise spacing of roughness elements in the array are...

Effect of Surface Roughness on Boundary Layer Transition and Far Field Noise

Surface roughness elements are often used to force laminar to turbulent transition during aerodynamic and aeroacoustic experiments in wind tunnels. The statistical features and frequency content of the forced turbulent boundary layer can influence the far-field trailing edge noise. To study this dependence, boundary layer transition induced by...