Numerical investigation on two airfoil analysis codes using the Euler and Navier-Stokes equations in inviscid and viscous flows

Under the framework of the DLG-CAE cooperation topic: 92-16, numerical investigation is carried out on two transonic airfoil analysis/design codes at the Institute of Design Aerodynamics, DLR, Braunschweig. The first is the DLR Airfoil Design Method based on the solutions of the Euler/Navier-Stokes eqs., and the other is the ISES Transonic Airfoil Analysis/Design code of MIT, which uses the Euler eqs. with viscous correction. This report summarizes the analysis part of the investigation where a DLR-2D Euler/Navier-Stokes code, which is the analysis part of the DLR Airfoil Design Method, is compared with ISES, running in direct mode, through numerical computations on several airfoils in inviscid and viscous flow conditions. The investigation suggests that both DLR-2D Euler/Navier-Stokes and the ISES codes are very powerful tools for the analysis of airfoils under subcritical and supercritical flow conditions, even with laminar separation bubbles and turbulent separations. Detailed discussions are made on parametric study, drag estimation, total pressure losses, and the features of different numerical algorithms, meshes and turbulent models involved. Viscous analysis results are compared with experimental data available and the CPU time needed for each code is also compared. (orig.)This work is under the DLR-CAE cooperation topic: 92-16, (Report 1)Available from TIB Hannover: RN 4165(1995,5) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Numerical investigation on two airfoil design codes based on the solutions of the Euler and Navier-Stokes equations

Under the framework of the DLR-CAE cooperation topic: 92-16, numerical investigation is carried out on two transonic airfoil analysis/design codes at the Institute of Design Aerodynamics, DLR, Braunschweig. The first code is the DLR Airfoil Design Method based on the solutions of the Euler/Navier-Stokes eqs., and the other is the ISES Transonic Airfoil Analysis/Design code of MIT, which uses the Euler eqs. with viscous correction. This report summarizes the design part of the investigation where both methods are compared with each other through design studies of transonic airfoils in inviscid and viscous flows. The design examples include the redesign of existing airfoils, design under ill-posed conditions, design with arbitrarily prescribed target Cp distributions, modifying NLF airfoils by changing the slopes of the favourable pressure gradients and the design of new NLF airfoils. The investigation suggests that both DLR Airfoil Design Method and the ISES code could be considered as very powerful tools for the design of transonic airfoils. They have successfully brought the accuracy of the inverse problem ot the same standard of the direct problem, that is, the solution of the Euler or Euler/NS equations. Great improvement has been achieved with the modifications to the orginal Takanashi's approach made by the DLR Airfoil Design Method. (orig.)This work is under the DLR-CAE cooperation topic: 92-16, (Report 2)Available from TIB Hannover: RN 4165(1995,6) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman