Investigation of Jet Effect on Aerodynamics of a launch vehicle using cluster of machines with GPU accelerators

For a launch vehicle, the base line aerodynamic coefficients are generated using wind tunnel tests at various Mach numbers, angles of attack and wind plane angles. Thereafter the contribution of differences in wind tunnel model and flight configuration, Reynolds number differences and Jet-on effect are quantified separately and included as incremental coefficients over the baseline data either using wind tunnel test or CFD studies. The study in this paper presents the effect of jet on the aerodynamic parameters of a launch vehicle which consists of a core and four strapons. Jet-on simulations are carried out on clean launch vehicle without protrusions and attachments for code-to-code verification. The results show a reduction in the coefficient of normal force (CN) and significant forward movement of center of pressure (XCp) for jet-on case which in turn causes more moment to act on the vehicle as compared to the jet-off case. Analysis shows that leeward side of the vehicle is affected to greater extent as compared to the windward side. Aerodynamic data in presence of multiple jets is computed using a cluster of machines with Graphic processing units (GPU) accelerators and methodology of parallel computation with GPU accelerators are also brought out.