Abstract :
Modications to design of airfoils for use in unsteady transonic flows are carried out by means of realistic geometry modeling and systematic removal of recompression shocks in the transonic region. A procedure for designing deformable airfoils for helicopter rotor blades is introduced. A baseline shock-free airfoil is created by combining systematic and optimization methods. Two analytical models of deformation are considered. Their ability to control dynamic stall is investigated numerically by using a two-dimensional, time-accurate, implicit Navier- Stokes code. Results indicate the great potential for the controlled deformation of airfoils for helicopter a pplica tions. Dynamic stalling of airfoils at high angles of a ttack and the appearance of strong recompression shocks at low angles of attack and high Mach numbers are reduced significantly. In this way, the results presented will help in extending the design knowledge base for airfoils for helicopter rotors with advanced dynamic stall control.
