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DSMC Study of Hypersonic Flows
Vignesh Ram P S,Kim Heuy Dong 한국추진공학회 2016 한국추진공학회 학술대회논문집 Vol.2016 No.12
The hypersonic flow around rectangular cylinder is studied using in-house developed DSMC solver. When the flow becomes rarefied the shock system will be affected and also the cases with high Knudsen number will be difficult to simulate using Navier – Stokes equation. DSMC method can provide accurate result for high Knudsen or rarefied flow regimes. In the present simulation the rectangular cylinder of 6 x 6 mm is investigated for a range of Mach number 2.0 – 5.0. The results shows that the shock gets smeared with increasing Knudsen number. Also the increasing Knudsen number shows that pressure load acting on the rectangular cylinder gets reduced.
Effect of Throat Area Ratio on Micro Nozzle Flows Using DSMC
Vignesh Ram P.S.,Heuy Dong Kim 한국추진공학회 2016 한국추진공학회 학술대회논문집 Vol.2016 No.5
Study of effect of throat area ratio on micro nozzle flows is carried out by using Direct Simulation Monte Carlo (DSMC) method. This method can be applied to a wide range of rarefied flows and is more appropriate to the flow regime where Kn>0.1. The objective of this study is to understand the flow features inside the micro nozzle by changing the throat area ratio. DSMC simulations are carried out by considering a non-reacting gas Nitrogen (N2) for various pressure ratios. Molecular collision is modeled by the variable hard sphere model and Larsen-Borgnakke statistical model is used to model energy exchange between kinetic and internal modes of species. This study revealed that at micro scale the exit pressure is matched without undergoing several shocks and by increasing the exit area shows the separation flow from the nozzle wall.
Effect of Vortex Generator on Cylindrical Body Aerodynamics at Mach 2.0
Vignesh Ram P.S.,Heuy-Dong Kim(김희동) 한국추진공학회 2014 한국추진공학회 학술대회논문집 Vol.2014 No.12
Experimental and computational studies were carried out to obtain the effect of vortex generator on cylindrical protrusion at Mach number 2.0. The experiments were performed using the supersonic blow down wind tunnel on different heights of cylindrical protrusion with vortex generator place ahead. The upstream and downstream flow around the cylindrical protrusion is influenced by vortex generator is observed by both visualization and pressure measurement techniques. Results obtained were compared with numerically simulated data. The results confirmed that aerodynamic drag acting on protrusion is reduced by adopting vortex generator ahead of cylindrical protrusion.