An analytical study is presented regarding the unsteady skin friction drag of an oscillating airfoil exposed to a fluctuating free stream speed. Both laminar and turbulent conditions are covered in the analysis. The unsteady potential flow pressure and velocity distributions required for the subsequent boundary layer analysis are obtained by an approximate development. The time-dependent boundary layer is solved by a finite difference scheme. It was found that depending on the values of the phase difference between free stream fluctuations and airfoil oscillations, reduced frequency, and amplitude of free stream fluctuations, the drag can either lead or lag the free stream.
No takes yet. Share an insight, caveat, or question.
Kottapalli et al. (1979) studied this question.
Synapse has enriched 5 related papers. Consider them for comparative context: