Engineering topics
Publications and source records attributed to Commerford, G. L..
Presented here is an automated training tool that engineers can use to master the application of NASTRAN to dynamic problems. Example problems were selected to make classical solutions available for comparison. These comparisons can be used to evaluate the solution.
Two methods for modeling dynamic stall have been developed. The alpha, A, B method generates lift and pitching moments as functions of angle of attack and its first two time derivatives. The coefficients are derived from experimental data for oscillating airfoils. The Time Delay Method generates the coefficients from steady state airfoil characteristics and an associated time delay in stall beyond the steady state stall angle. Correlation with three types of test data shows that the alpha, A, B method is somewhat better for use in predicting helicopter rotor response in forward flight. Correlation with lift and moment hysteresis loops generated for oscillating airfoils was good for both models.