Numerical prediction of shock/boundary-layer interactions at high Mach numbers using a modified Spalart–Allmaras model

Pasha, Amjad Ali; Juhany, Khalid A.; Khalid, M.

doi:10.1080/19942060.2018.1451389

Cited by 12 publications

(10 citation statements)

References 33 publications

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“…The high-velocity exhaust gas impingement on the flame deflector is calculated by the realizable k-ε turbulence model, which is suitable for the flow field near the wall (Ali et al, 2018;El-Amin et al, 2010). The transport equations for turbulence kinetic energy (k) and its rate of dissipation (ε) are given as…”

Section: Methodsmentioning

confidence: 99%

Numerical study for the flame deflector design of four-engine liquid rockets

Zhou

Zhang²,

2020

Engineering Applications of Computational Fluid Mechanics

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The thermal environment of four-engine liquid rocket exhaust plume impinging on the flame deflector with different impingement and uplift angles is analysed. The supersonic exhaust gas impinging model was established by using the compressible, multi-component, Reynolds-Averaged Navier-Stokes (RANS) equations with the finite volume method. A comparison between the numerical results and experimental data in the literature is made, which verified the validity and accuracy of the numerical model. Additionally, the flow fields of the four-engine rocket impinging on the flame deflector under different impingement and uplift angles are simulated. The results show that high temperatures on the deflector surface mainly occur on the impingement point or the cambered surface. A large impingement angle causes the reverse flow intensity to increase whilst a small angle causes the exhaust gas to deflect a little, a suitable uplift angle can smoothly guide the exhaust gas away from the deflector that the best thermal environment of the deflector channel appears at an impingement angle of 25°and an uplift angle of 5°. This study demonstrates that our model can effectively simulate the impinging flow field, and can be of use for the design of the flame deflector under the multi-engine rocket exhaust gas impact.

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Section: Methodsmentioning

confidence: 99%

Numerical study for the flame deflector design of four-engine liquid rockets

Zhou

Zhang²,

2020

Engineering Applications of Computational Fluid Mechanics

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“…The code has been used and validated in several supersonic and hypersonic shock/boundarylayer interaction flows. [19][20][21] The number of grid points is increased in both the streamwise and normal directions from 900 3 300 to 1300 3 500 until the solution is independent of the grid as shown in Figure 2. Therefore, based on the grid convergence study, there is a less than 1% difference between 1300 3 500 and 1100 3 400 grids.…”

Section: Numerical Methodologymentioning

confidence: 99%

Effect of wall temperature on separation bubble size in laminar hypersonic shock/boundary layer interaction flows

Pasha

Juhany

2019

Advances in Mechanical Engineering

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At hypersonic speeds, the external wall temperatures of an aerospace vehicle vary significantly. As a result, there is a considerable heat transfer variation between the boundary layer and the wall of the hypersonic vehicle. In this article, numerical computations are performed to investigate the effect of wall temperature on the separation bubble length in laminar hypersonic shock-wave/boundary-layer interaction flows over double-cone configuration at the Mach number of 12.2. The flow field is described in detail in terms of different shocks, expansion fans, shear layer and separation bubble. The variation of the Prandtl number has a negligible effect on the flow field and wall data. A specific heat ratio of less than 1.4 results in the better prediction of wall pressure and heat flux in the shock/boundary-layer interaction region. It is observed that as the wall temperature is increased, the separation bubble size and hence the separation shock length increases. The high firmness of the laminar boundary-layer at a high Mach number shows that the wall temperature in the shock/boundary-layer interaction region has little effect. The peak wall pressure and heat flux decrease with an increase in wall temperature. An estimation is developed between separation bubble length and wall temperature based on the computed results.

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“…In our efforts to optimize the model, it is obviously time consuming to perform a great deal of CFD simulations, one way to overcome that is to simplify the grid model and use some advanced turbulence model like modified Spalart-Allmaras model (Pasha, Juhany, & Khalid, 2018) to predict the boundary-layer interactions. Also, it can be solved by an alternative better performed method than the calculation of the CFD tools Fotovatikhah et al, 2018).…”

Section: Optimization Proceduresmentioning

confidence: 99%

Application and optimization of drag reduction characteristics on the flow around a partial grooved cylinder by using the response surface method

Song

Zhang

et al. 2019

Engineering Applications of Computational Fluid Mechanics

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It is well known that drag reduction occurs when the flow is passing by a grooved circular cylinder at certain Reynolds numbers, which has been used as a powerful energy saving method in a broad range of circumstances. However, a challenge here is how to evaluate the combined effects of depth, width and location of a given triangular groove set covering half of the cylindrical surface area. A useful approach to quantitatively analyze the influence of these different factors on drag reduction using the response surface methodology is described here. The flow characteristics, including drag coefficient, flow velocity, turbulent kinetic energy and vorticity, were calculated by numerical simulation. The results showed a great drag reduction effect under the legitimate set of groove structure parameters at a super-critical Reynolds number providing a base for optimization process in various engineering applications. The drag reduction mechanism found from this research could extend to other cases and should provide insights into engineering applications like car grilles. ARTICLE HISTORY

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Numerical prediction of shock/boundary-layer interactions at high Mach numbers using a modified Spalart–Allmaras model

Cited by 12 publications

References 33 publications

Numerical study for the flame deflector design of four-engine liquid rockets

Numerical study for the flame deflector design of four-engine liquid rockets

Effect of wall temperature on separation bubble size in laminar hypersonic shock/boundary layer interaction flows

Application and optimization of drag reduction characteristics on the flow around a partial grooved cylinder by using the response surface method

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