7th Symposium on Applied Aerodynamics And Design of Aerospace Vehicles
Low enthalpy turbulent flows pertaining to 2D scramjet inlets are characterized by strong entropy... more Low enthalpy turbulent flows pertaining to 2D scramjet inlets are characterized by strong entropy gradients in the flow field, massive viscous dissipation, complicated shock-shock interactions and shock-wave boundary layer interactions. Prediction of these phenomena using numerical simulations still remains a major hurdle. In the present study, turbulent RANS simulations were carried out over standard test cases pertaining to two dimensional scramjet inlets using Spalart - Allmaras (SA) and k-ω turbulence models. Qualitative and quantitative comparisons were made with the experimental Results and other CFD solvers. Results indicate that, k-ω SST turbulence model can predict, the aerodynamic heating phenomena better compared to SA and is recommended for use in such flow regimes.
Waverider is a lifting body tailored to create high lift to drag ratio in high speed flow. Presen... more Waverider is a lifting body tailored to create high lift to drag ratio in high speed flow. Present work includes optimization of power law derived waverider using TLBO for a design altitude of 30km at zero design angle of attack and for a range of angle of attack from -2 to 6 for inviscid, laminar and turbulent cases at design Mach number from 5 to 8. Optimised waverider geometry parameters for all three cases are compared for two objective functions; (a) maximization of lift to drag ratio and (b) maximization of lift to drag ratio and volume along with minimization of heat flux (represented by wetted area in present study). Dependence of n, δ and λ (design variables) on lift to drag ratio is discussed in detail. Numerical and experimental validation of the analytical model shows a close match with the data available in the literature. Despite having some limitations, this model serves as a valuable design tool in the conceptual phase to arrive at optimised waverider configurations. Optimization function can be changed according to the designer’s requirements.
The supersonic combustion ramjet (scramjet) engine proposed by F.S.Billig in 1964 has been percei... more The supersonic combustion ramjet (scramjet) engine proposed by F.S.Billig in 1964 has been perceived as the most hopeful air breathing propulsion system for the hypersonic flight. The nozzle plays a vital role in accelerating heated air from the combustor to produce thrust in a scramjet engine. In the present study a design methodology has been established using in-house developed python script for the automation process of Computational Fluid Dynamics (CFD), Artificial Neural Network (ANN) and optimization. The nozzle geometry used in this method consist of the inner surface which is represented by a cubic curve. The optimization is carried out for a hypersonic cruise vehicle nozzle designed to fly at Mach number of 6 and an altitude of 30km with single expansion ramp nozzle as the baseline geometry. The results show that the optimized nozzle contour generates 16.7% more thrust when compared to the baseline geometry for similar flow conditions.
Hypersonic waverider configurations are promising candidates for future space and defence applica... more Hypersonic waverider configurations are promising candidates for future space and defence applications as they meet the stringent demands of aerodynamic efficiency at high Mach numbers. An attempt has been made here to study the high angle of attack characteristics of such configurations at hypersonic Mach numbers using HiFUN. At high angle of attacks the simulations compares well with the Newtonian theory as the upper surface pressures are negligible compared to the lower surface pressures. The aerodynamic efficiency is maximum at 4 degree and the configuration stalls at 45 degree.
7th Symposium on Applied Aerodynamics And Design of Aerospace Vehicles
Low enthalpy turbulent flows pertaining to 2D scramjet inlets are characterized by strong entropy... more Low enthalpy turbulent flows pertaining to 2D scramjet inlets are characterized by strong entropy gradients in the flow field, massive viscous dissipation, complicated shock-shock interactions and shock-wave boundary layer interactions. Prediction of these phenomena using numerical simulations still remains a major hurdle. In the present study, turbulent RANS simulations were carried out over standard test cases pertaining to two dimensional scramjet inlets using Spalart - Allmaras (SA) and k-ω turbulence models. Qualitative and quantitative comparisons were made with the experimental Results and other CFD solvers. Results indicate that, k-ω SST turbulence model can predict, the aerodynamic heating phenomena better compared to SA and is recommended for use in such flow regimes.
Waverider is a lifting body tailored to create high lift to drag ratio in high speed flow. Presen... more Waverider is a lifting body tailored to create high lift to drag ratio in high speed flow. Present work includes optimization of power law derived waverider using TLBO for a design altitude of 30km at zero design angle of attack and for a range of angle of attack from -2 to 6 for inviscid, laminar and turbulent cases at design Mach number from 5 to 8. Optimised waverider geometry parameters for all three cases are compared for two objective functions; (a) maximization of lift to drag ratio and (b) maximization of lift to drag ratio and volume along with minimization of heat flux (represented by wetted area in present study). Dependence of n, δ and λ (design variables) on lift to drag ratio is discussed in detail. Numerical and experimental validation of the analytical model shows a close match with the data available in the literature. Despite having some limitations, this model serves as a valuable design tool in the conceptual phase to arrive at optimised waverider configurations. Optimization function can be changed according to the designer’s requirements.
The supersonic combustion ramjet (scramjet) engine proposed by F.S.Billig in 1964 has been percei... more The supersonic combustion ramjet (scramjet) engine proposed by F.S.Billig in 1964 has been perceived as the most hopeful air breathing propulsion system for the hypersonic flight. The nozzle plays a vital role in accelerating heated air from the combustor to produce thrust in a scramjet engine. In the present study a design methodology has been established using in-house developed python script for the automation process of Computational Fluid Dynamics (CFD), Artificial Neural Network (ANN) and optimization. The nozzle geometry used in this method consist of the inner surface which is represented by a cubic curve. The optimization is carried out for a hypersonic cruise vehicle nozzle designed to fly at Mach number of 6 and an altitude of 30km with single expansion ramp nozzle as the baseline geometry. The results show that the optimized nozzle contour generates 16.7% more thrust when compared to the baseline geometry for similar flow conditions.
Hypersonic waverider configurations are promising candidates for future space and defence applica... more Hypersonic waverider configurations are promising candidates for future space and defence applications as they meet the stringent demands of aerodynamic efficiency at high Mach numbers. An attempt has been made here to study the high angle of attack characteristics of such configurations at hypersonic Mach numbers using HiFUN. At high angle of attacks the simulations compares well with the Newtonian theory as the upper surface pressures are negligible compared to the lower surface pressures. The aerodynamic efficiency is maximum at 4 degree and the configuration stalls at 45 degree.
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Papers by Manoj Kumar