DisPLACEMENT EEFeCTSaF OuMpARy LAYER oN PBrENTAL FLow E BL lo BL Acx4.F∠ ye 4())=引力 ye dx :-女 :(25)-% where 之么 E55 DISPLACEMENT BoDy Flow tangent 如d.bol ) =(2)-%会→ WaLL 3 MODEL vall/*) bw∥ ,业会1→业·5足