Delusive Influence of Nondimensional Numbers in Canonical Hypersonic Nonequilibrium Flows

Desai, Siddesh; Kulkarni, Vinayak; Gadgil, Hrishikesh

doi:10.1061/(asce)as.1943-5525.0000620

Cited by 18 publications

(5 citation statements)

References 26 publications

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“…The validation details of this solver with numerical as well as experimental results are reported in the literature. 28–32 Additionally, simulations are performed to reproduce the experimental works of Mallinson. 33 The opted geometry consists of a 0.085 m long flat plate ( L c ) and 18° ramp of 0.095 m length.…”

Section: Numerical Methodologymentioning

confidence: 99%

Comparative studies of shock-wave boundary-layer interactions in Earth and Mars atmospheres

Das

Desai

Kulkarni

2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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Investigations of ramp-induced shock-wave boundary-layer interaction have been carried out for real gas flows of air and carbon dioxide through hypersonic laminar flow simulations corresponding to Earth and Mars atmospheres. An in-house-developed solver, which accounts for the real gas effects, has been employed for these studies. Effects of various parameters like wall temperature, freestream stagnation enthalpy, freestream Mach number, and blunt leading edge are explored on the intensity of shock-wave boundary-layer interaction (SWBLI). In either case, an increase in separation length is observed with an increase in wall temperature and a decrease in Mach number as well as freestream stagnation enthalpy. Here, the intensity of alteration is always noted to have a higher percentage for the Mars gas model. Further, separation length is found to be almost equal for the same wall to total temperature ratio in both of the flow mediums. The present study also affirms the fact that the leading edge bluntness can be used as a tool to reduce the size of the separation region in these planetary atmospheres. Revised correlations have been proposed for hypersonic Earth atmospheric flow with real gas effects to predict the extent of upstream influence and separation bubble size. The outcomes of simulations have also helped to device new correlations for these flow features of SWBLI for Mars atmospheric conditions. In all, the need for consideration of real gas effects and an exclusive real gas flow solver for the Mars atmosphere are the prominent recommendations of current studies.

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Section: Numerical Methodologymentioning

confidence: 99%

Comparative studies of shock-wave boundary-layer interactions in Earth and Mars atmospheres

Das

Desai

Kulkarni

2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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“…Two types of finite volume based two-dimensional simulations are performed for R-SWBLI under laminar flow assumption. Perfect gas solver 21,23,24 is used for low enthalpy simulations while nonequilibrium flow solver 25–27 is employed for high enthalpy condition only. Conventional Navier–Stokes equations are solved for perfect gas flow simulations.…”

Section: Numerical Methodologymentioning

confidence: 99%

Separation mitigation using pressure feedback technique for hypersonic shock wave boundary layer interaction

Desai

Kulkarni

Gadgil

2018

Proceedings of the Institution of Mechanical Engineers, Part G:

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Present studies are focused on the use of pressure feedback technique as a separation control technique for ramp induced flow separation at hypersonic speed. Numerical simulations portrayed that though pressure feedback technique can reduce the flow separation, further cooling of the feedback channel enhances its potential for separation control. Marginal cooling of channel walls to 175 K has reduced separation bubble size by 18.18% while strong cooling of those walls to 50 K reduced the separation by 30%. Such low enthalpy perfect gas simulations also showed the lower effectiveness of pressure feedback technique with increased ramp angle. Further, it has been noticed from the perfect and nonequilibrium gas flow simulations that the cooling of pressure feedback channel introduces differential separation size for the same wall-to-total temperature ratio cases. Integration of cooled pressure feedback channel with blunt leading edge configuration showed reduced separation size for any bluntness radius. Effectiveness of this integration is seen in lowering the values of inversion and equivalent radii. Thus, use of cooled pressure feedback technique in conjunction with leading edge bluntness is not only seen to have reduced the intensity of shock wave boundary layer interaction but also has enhanced the controllability of blunted leading edge without altering the entropy layer–boundary layer interaction.

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“…When simulating for Earth's atmosphere, the solver considers five species (N 2 , O 2 , N, O, and NO) model with 11 chemical reactions, 25 whereas for Mars atmosphere, eight species (N 2 , O 2 , N, O, NO, CO 2 , CO, and C) model with 10 chemical reactions 26 is considered. The governing equations coupled with the species continuity equation for this 2D solver are represented in vector form in Equation (1).…”

Section: Numerical Formulationmentioning

confidence: 99%

“…Therefore, point ( 1) is marked at M ∞ polar at θ = 4°. Further, from point (1), M 1 polar has to be drawn with Mach number and specific heat ratio of the region (1). Now, as the flow in the region (2) must be parallel to the wall, therefore, point (2) should be at θ = 0°(zero deflection line), and also it should be in M 1 polar.…”

Section: Effect Of Freestream Stagnation Enthalpymentioning

confidence: 99%

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Shock/expansion fan interaction with real gas effects for Earth and Mars atmospheric conditions

2022

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Numerical simulations are performed to investigate the real gas effects on shock/expansion fan interaction. Initial perfect gas simulations at low enthalpy capture the flow structures efficiently and outcomes are found to have excellent agreement with the analytical calculations. Furthermore, the simulations with the real gas solver for different enthalpies showed that the variation in enthalpy significantly changes the flow structures. It is observed that an increase in enthalpy leads to a decrease and increase in the postshock and postexpansion fan Mach numbers, respectively. Another important observation is the decrement in the peak pressure ratio with an increment in the enthalpy. These effects are noted to be more pronounced for Mars's environment due to the higher dependency of specific heat on temperature.computational fluid dynamics, Earth and Martian atmospheric simulations, expansion fan, hypersonic flow, real gas flow, shock waves | INTRODUCTIONThe design of high-speed 1,2 aircraft necessitates the appropriate predictions of flow structures associated with it. These flights often encounter shocks and expansion fans. Furthermore, these shock waves and expansion fans may interact with each other. The presence of shock/ expansion fan interaction may complicate the flow structures by affecting the boundary-layer

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Delusive Influence of Nondimensional Numbers in Canonical Hypersonic Nonequilibrium Flows

Cited by 18 publications

References 26 publications

Comparative studies of shock-wave boundary-layer interactions in Earth and Mars atmospheres

Comparative studies of shock-wave boundary-layer interactions in Earth and Mars atmospheres

Separation mitigation using pressure feedback technique for hypersonic shock wave boundary layer interaction

Shock/expansion fan interaction with real gas effects for Earth and Mars atmospheric conditions

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