Author : Robert M. Bennett
Release : 2000
Genre :
Kind : eBook
Book Rating : /5 ( reviews)

GET EBOOK

Book Synopsis Test Cases for a Rectangular Supercritical Wing Undergoing Pitching Oscillations by : Robert M. Bennett

Download or read book Test Cases for a Rectangular Supercritical Wing Undergoing Pitching Oscillations written by Robert M. Bennett. This book was released on 2000. Available in PDF, EPUB and Kindle. Book excerpt: Steady and unsteady measured pressures for a Rectangular Supercritical Wing (RSW) undergoing pitching oscillations have been presented in Ref I to 3. From the several hundred compiled data points, 27 static and 36 pitching oscillation cases have been proposed for computational Test Cases to illustrate the trends with Mach number, reduced frequency, and angle of attack. The wing was designed to be a simple configuration for Computational Fluid Dynamics (CFD) comparisons. The wing had an unswept rectangular planform plus a tip of revolution, a panel aspect ratio of 2.0, a twelve per cent thick supercritical airfoil section, and no twiSt The model was tested over a wide range of Mach numbers, from 0.27 to 0.90, corresponding to low subsonic flows up to strong transonic flows. The higher Mach numbers are well beyond the design Mach number such as might be required for flutter verification beyond cruise conditions. The pitching oscillations covered a broad range of reduced frequencies. Some early calculations for this wing are given for lifting pressure in Ref 3 and 4 as calculated from a linear lifting surface program and from a transonic small perturbation program. The unsteady results were given primarily for a mild transonic condition at M = 0.70. For these cases the agreement with the data was only fair, possibly resulting from the omission of viscous effects. Supercritical airfoil sections are known to be sensitive to viscous effects (for example, one case cited in Ref 4). Calculations using a higher level code with the full potential equations have been presented in Ref 5 for one of the same cases, and with the Euler equations in Ref 6. The agreement around the leading edge was improved, but overall the agreement was not completely satisfactory.