Wall Pressure Fluctuations in a Turbulent Boundary Layer After Blowing or Suction

A direct numerical simulation of a spatially developing turbulent boundary layer is performed to examine the characteristics of wall pressure e uctuations after the sudden application of wall blowing or suction. The uniform blowing or suction is given by the wall-normal velocity through a spanwise slot at the wall. The response of wall pressure e uctuations to uniform blowing or suction is analyzed by computing the turbulence statistics and frequencyspectra.Itisfoundthatwallpressuree uctuationsaremoreaffectedbyblowingthanbysuction.Thelarge elongated structureofwallpressuree uctuationsisobservednearthemaximum locationof (pw)rms forblowing.The convection velocities for blowing increase with increasing the streamwise location after the slot. For both blowing and suction, the small scale of wall pressure e uctuations reacts in a short downstream distance to the spanwise slot, whereas the large scale recovers slowly farther downstream.