A CFD Tutorial in Julia: Introduction to Compressible Laminar Boundary-Layer Flows

Oz, Furkan; Kara, Kursat

doi:10.3390/fluids6110400

Cited by 12 publications

(4 citation statements)

References 37 publications

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“…In this study, the nose radius is selected to be small enough to diminish the stabilization effect of the entropy layer 17 , 57 , 59 , 60 . Additionally, the steady flow boundary layer velocity and temperature profiles are compared with the similarity solution 61 , 62 in Fig. 5 , and an excellent agreement is found.…”

Section: Resultsmentioning

confidence: 72%

Controlling hypersonic boundary layer transition with localized cooling and metasurface treatments

Oz,

Kara

2024

Sci Rep

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This study investigates a novel method to control hypersonic boundary layer transition using a combined local cooling and local metasurface treatment. The method’s effectiveness was investigated on a 5-degree half-angle blunt wedge with a nose radius of 0.0254 mm at a freestream Mach number of 6.0 using direct numerical simulations and linear stability theory. We explored four cases: (i) adiabatic baseline case, (ii) locally cooled case, (iii) local metasurface case, and (iv) combined local cooling-local metasurface case. Results showed that the combined local cooling-local metasurface treatment significantly reduced both wall pressure disturbance amplitude and the density perturbation amplitude around the sonic line, indicating a potential for controlling hypersonic boundary layer transition. In the local cooling-local metasurface case, the disturbance amplitude at the end of the computational domain was 270 times lower than the baseline case. The study also examined the impact of Reynolds numbers, ranging from 25.59 million per meter to 32.80 million per meter. Unsteady simulations revealed that the Reynolds number had a negligible effect on the local cooling-local metasurface performance, indicating that the proposed method applies to a wide range of flight conditions.

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Section: Resultsmentioning

confidence: 72%

Controlling hypersonic boundary layer transition with localized cooling and metasurface treatments

Oz,

Kara

2024

Sci Rep

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“…1. 117,118 Hereafter, we investigate the ability of the present family of positivist-preserving LB schemes to correctly simulate the development of the above compressible laminar boundary layer in the supersonic regime. The Reynolds, Mach, and Prandtl numbers are fixed to 10 000, 1.5, and 1, respectively.…”

Section: E Compressible Laminar Boundary Layermentioning

confidence: 99%

Exponential distribution functions for positivity-preserving lattice Boltzmann schemes: Application to 2D compressible flow simulations

Thyagarajan,

Coreixas,

Latt

2023

Physics of Fluids

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A family of positivity-preserving lattice Boltzmann methods (LBMs) is proposed for compressible flow simulations in the continuum regime. It relies on the efficient collide-and-stream algorithm with a collision step based on exponential distribution functions. The latter serves as a generalization of Grad's post-collision distribution functions for which here (1) the linearized non-equilibrium contributions are replaced by their exponential forms and (2) the number of these contributions can be chosen arbitrary. In practice, post-collision moments of our exponential formulation are enforced through an iterative moment-matching approach to recover any macroscopic physics of interest, with or without external forces. This methodology directly flows from the extended framework on numerical equilibria [J. Latt et al., Philos. Trans. R. Soc. A 378, 20190559 (2020)] and goes one step further by allowing for the independent relaxation of hydrodynamic and high-order modes in a given moment space, notably, making the Prandtl number freely adjustable. The model is supplemented by a shock-capturing technique, based on the deviation of non-equilibrium moments from their equilibrium counterparts, to ensure good numerical properties of the model in inviscid and under-resolved conditions. A second exponential distribution accounts for extra degrees of freedom of molecules and allows for the simulation of polyatomic gases. To validate this novel approach and to quantify the accuracy of different lattices and moment closures, several 2D benchmark tests of increasing complexity are considered: double shear layer, linear wave decay, Poiseuille flow, Riemann problem, compressible Blasius flow over a flat plate, and supersonic flow past an airfoil. Corresponding results confirm the accuracy and stability properties of our approach for the simulation of compressible flows with LBMs. Eventually, the performance analysis further highlights its efficiency on general purpose graphical processing units.

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“…In solution to the boundary layer equation from its analysis, key flow parameters like velocity and pressure profiles are established. The boundary layer equation is a partial differential equation from a simplified Navier-Stokes equation [7].…”

Section: Introductionmentioning

confidence: 99%

“…Prandtl divided flow over a surface into the main flow region and the boundary layer flow region. This understanding has made it possible to simplify the Navier-Stokes equations [7].…”

Section: Introductionmentioning

confidence: 99%

Boundary Layer Fluid Flow in Volume Chamber of Cavitating Gerotor Pump: Computational Analysis using MATLAB

Ile,

Ngonda

2024

Preprint

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Gerotor pumps are widely used in the lubrication system of automobile combustion engines, known for their simplicity and efficiency. This paper presents a computational study of boundary layer flow for volume chamber of a gerotor pump experiencing cavitation. Utilizing MATLAB, we investigate the feasibility of using boundary layer approximation to monitor the adversity of the condition. The implementation is done by developing a finite element code to solve the boundary layer equation, for an arc length (0 to 1 mm) using experimental data. The focus is on understanding the fluid dynamics of the pump within the pump volume chamber, which plays a crucial role in the pump's overall performance. Solving the boundary layer equation, we simulated the flow characteristics within the pump volume chamber and generated results of Reynolds number, velocity profile, boundary layer thickness, and pressure energy profile. The main measure is the pressure energy parameter which shows analysis of the work done in moving the fluid against the resistance created by the cavitation. As expected, the results revealed a high correlation of cavitation with the suction pressure. This influence is seen to affect the overall delivered oil flow rate, while no interest was placed on other parameters outside the pump chamber flow characteristics. Furthermore, pressure ripples from the surface plot of the velocity profile show evidence of re-circulation or separation zones along the arc length.

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A CFD Tutorial in Julia: Introduction to Compressible Laminar Boundary-Layer Flows

Cited by 12 publications

References 37 publications

Controlling hypersonic boundary layer transition with localized cooling and metasurface treatments

Controlling hypersonic boundary layer transition with localized cooling and metasurface treatments

Exponential distribution functions for positivity-preserving lattice Boltzmann schemes: Application to 2D compressible flow simulations

Boundary Layer Fluid Flow in Volume Chamber of Cavitating Gerotor Pump: Computational Analysis using MATLAB

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