Meshless kinetic upwind method for compressible, viscous rotating flows

Mahendra, A.K.; Singh, Ram Kumar; Gouthaman, G.

doi:10.1016/j.compfluid.2010.10.015

Cited by 10 publications

(4 citation statements)

References 25 publications

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“…This enables us to get a singlestep higher-order meshless method. It is in this respect that the present solver is distinctly different from the work of Mahindra et al (2011) and Anandhanarayanan, Nagarathinam, and Deshpande (2004).…”

contrasting

confidence: 64%

“…Zhau and Xu (2010) used the meshless method to compute an unsteady flow field over the NACA 0012 and NACA 0008 airfoils. Mahindra, Singh, and Gouthaman (2011) used an LSKUM-based solver to compute the viscous rotating flow. They observed the ill-conditioning of a least square problem when an explicit LSKUM solver operates on the stretched distribution of points near a boundary, which is required to capture viscous flow features.…”

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confidence: 99%

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Implicit scheme for meshless compressible Euler solver

Singh

Ramesh

Balakrishnan

2015

Engineering Applications of Computational Fluid Mechanics

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In this paper, an implicit scheme is presented for a meshless compressible Euler solver based on the Least Square Kinetic Upwind Method (LSKUM). The Jameson and Yoon's split flux Jacobians formulation is very popular in finite volume methodology, which leads to a scalar diagonal dominant matrix for an efficient implicit procedure . However, this approach leads to a block diagonal matrix when applied to the LSKUM meshless method. The above split flux Jacobian formulation, along with a matrix-free approach, has been adopted to obtain a diagonally dominant, robust and cheap implicit time integration scheme. The efficacy of the scheme is demonstrated by computing 2D flow past a NACA 0012 airfoil under subsonic, transonic and supersonic flow conditions. The results obtained are compared with available experiments and other reliable computational fluid dynamics (CFD) results. The present implicit formulation shows good convergence acceleration over the RK4 explicit procedure. Further, the accuracy and robustness of the scheme in 3D is demonstrated by computing the flow past an ONERA M6 wing and a clipped delta wing with aileron deflection. The computed results show good agreement with wind tunnel experiments and other CFD computations.

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confidence: 64%

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confidence: 99%

Implicit scheme for meshless compressible Euler solver

Singh

Ramesh

Balakrishnan

2015

Engineering Applications of Computational Fluid Mechanics

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“…They work on a cloud of points on which PDEs can be discretized. Various meshless schemes have been applied to compressible viscous flows with a great deal of accuracy, and have compared well with the results obtained from finite-volume schemes [42,49,76,35,41]. A description of the meshless method used in our non-equilibrium model, which we call the Meshless Line Solver (MLS), is given in the following section.…”

Section: Non-equilibrium Modelmentioning

confidence: 99%

Wall modeled LES of compressible flows at non-equilibrium conditions

Mettu

Subbareddy

2018

2018 Fluid Dynamics Conference

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METTU, BALACHANDRA REDDY. Wall Modeled LES of Compressible Flows in Non-Equilibrium Conditions. (Under the direction of Pramod Subbareddy.)A turbulent boundary layer is composed of a wide range of length scales and time scales. To resolve all these scales of motion, as with a DNS or traditional wall resolved LES, the grid sizes required scale roughly as the square/cube of the Reynolds number (Re). These requirements make high Re flows computationally very expensive. By modeling the effect of the motions close to the wall, as is proposed in wall modeled LES (WMLES) methods, the computation of high Re flows can be made significantly cheaper. To date, WMLES has been relatively less studied in application with strong compressibility effects.In this study, we implement state-of-the-art wall models for these flows and examine the different challenges which are common to high-speed flow applications: isothermal cold wall conditions, the transition to turbulence, and shock boundary layer interactions (SBLI). It is observed that for cold-wall flows, a more empirical "mixed" scaling for the length scale appearing in the eddy viscosity formulation outperforms the classical semi-local scaling for obtaining predictions of heat-flux and skin-friction. For transitional flows, we develop a modified transition sensor that gave robust predictions for the high Mach number cases we examined. We find that the more computationally expensive non-equilibrium model with an eddy viscosity formulation based on the pressure gradient outperformed the standard equilibrium model for skin-friction predictions in SBLIs. A sensor for detecting regions of non-equilibrium flow was developed based on the resolved Reynolds stress. By using this sensor and switching to an exchange location closer to the wall in the non-equilibrium region for the equilibrium model gave skin-friction and heat flux results close to or even better than the non-equilibrium model at a far cheaper cost. WMLES was performed for SBLI at moderate to high Re with different wall temperature conditions. It was observed that WMLES was able to capture the expansion and shrinking of the separation bubble size when the wall was heated and cooled. Also observed was that using WMLES the low-frequency characteristics of SBLI at high Re was now possible. As a whole, it was seen that WMLES can become a promising tool for exploring the complex physics involved in turbulent high-speed flows at a significantly lower cost than wall resolved LES/DNS and with much higher fidelity compared to pure RANS simulations.

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“…The compressible flow CFD solver used was Split stencil Least squares Kinetic upwind method for Navier Stokes (SLKNS) [15], which makes use of split stencil least squares and Kinetic Flux Vector Splitting [16]. The usefulness of meshless flow solver was exploited by avoiding regridding after each shape change of airfoil [21].…”

Section: Test Casementioning

confidence: 99%