A method to determine wall shear stress from mean profiles in turbulent boundary layers

The direct measurement of wall shear stress in turbulent boundary layers (TBL) is challenging, therefore, requiring it to be indirectly determined from mean profile measurements. Most popular methods assume the streamwise velocity satisfy either a logarithmic law inner layer or composite with many tuned constants for entire TBL, both which require reliable data layer. presence roughness and pressure gradient brings additional complications where most existing fail significant modification. A novel method proposed determine zero TBL measured profiles, without near-wall data. based on model Kumar Mahesh (Phys Rev Fluids 6:024603, 2021), who developed accurate models wall-normal TBL. requires single point outer layer, preferably between 20 $$50 \%$$ an estimate thickness shape factor. can handle modification shown predict friction velocities within $$3 over range Reynolds number smooth rough In order include gradients effects, work 2021) revisited derive then used formulate obtain Overall, robust variety