Three-dimensional, conservative, Euler computations using patched grid systems and explicit methods

Hessenius, Kristin A.; M., M.

doi:10.2514/6.1986-1081

Cited by 19 publications

(1 citation statement)

References 6 publications

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“…Multiply-connected domains in two-dimensions or complex simply- [47][48][49][50][51][52] have been quite successful in patching structured grids together in order to cover the entire computational domain. Benek, Burring, and Steger [53] have overlapped structured grids in three-dimensions.…”

Section: List Of Illustrationsmentioning

confidence: 99%

Two-dimensional Euler computations on a triangular mesh using an upwind, finite-volume scheme

Whitaker

Grossman

Löhner

1989

27th Aerospace Sciences Meeting

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Aerospace Engineering (ABSTRACT)A new numerical procedure has been developed for the finite-volume solution of the Euler equations on unstructured, triangular meshes using a flux-difference split, upwind method. The procedure uses a dual mesh system to implement the finite-volume scheme using conserved variables stored at the vertices of the triangles. The vertices of the triangles are located approximately in the center of the dual mesh cells and conservation is enforced about each dual mesh finite-volume.Techniques are developed for implementing Roe's approximate Riemann solver on unstructured grids.Higher order accuracy is achieved by using MUSCL-differencing. MUSCL-differencing is implemented on an unstructured grid by interpolating the values stored at the vertices of triangular elements to find the value at the outermost point of the three-point MUSCL-differencing formula. Flow solutions are computed using a four-stage Runge-Kutta time integration. Convergence is accelerated using non-standard weighting of the Runge-Kutta stages, variable time-steps, residual smoothing and residual minimization. Applications and comparisons with structured grid solutions are made for a supersonic shock reflection problem, the supersonic flow over a blunt body, flow through a simple wedge inlet, and several AGARD 07 working group transonic airfoils. In general, the solutions computed by the upwind solver on the unstructured grids were as accurate as upwind solutions on a structured mesh.The blunt body solution, and some of the transonic airfoil solutions on the unstructured meshes, appeared to be less accurate than the structured mesh solutions. Fortuitously, the structured meshes used in these solutions tended to line up with the shock waves present in the flow-field. The upwind flux-differencing scheme captured the shock wave with greatest accuracy when it was applied normal to the discontinuity, as was done in these test cases.

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Section: List Of Illustrationsmentioning

confidence: 99%

Two-dimensional Euler computations on a triangular mesh using an upwind, finite-volume scheme

Whitaker

Grossman

Löhner

1989

27th Aerospace Sciences Meeting

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Algebraic grid generation for complex geometries

Shih

Bailey

Nguyen

et al. 1991

Numerical Methods in Fluids

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SUMMARYAn efficient computer programme called GRID2D/3D has been developed to generate single and composite grid systems within geometrically complex two-and three-dimensional (2D and 3D) spatial domains that can deform with time. GRID2D/3D generates single grid systems by using algebraic grid generation methods based on transfinite interpolation. The distribution of grid points within the spatial domain is controlled by stretching functions and grid lines can intersect boundaries of the spatial domain orthogonally. GRID2D/3D generates composite grid systems by patching together two or more single grid systems. The patching can be discontinuous or continuous. For 2D spatial domains the boundary curves are constructed by using either cubic or tension spline interpolation. For 3D spatial domains the boundary surfaces are constructed by using a new technique, developed in this study, referred to as 3D bidirectional Hermite interpolation.

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Unsteady aerodynamic loads on high speed trains passing by each other

Hwang¹,

Lee²

2000

KSME International Journal

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In order to study unsteady aerodynamic loads on high speed trains passing by each other 350km/h, three-dimensional flow fields around trains during the crossing event are numerically simulated using three-dimensional Euler equations. Roe's FDS with MUSCL interpolation is employed to simulate wave phenomena. An efficient moving grid system based on domain decomposition techniques is developed to analyze the unsteady flow field induced by the restricted motion of a train on a rail. Numerical simulations of the trains passing by on the double-track are carried out to study the effect of the train nose-shape, length and the existence of a tunnel on the crossing event. Unsteady aerodynamic loads-a side force and a drag force -acting on the train during the crossing are numerically predicted and analyzed. The side force mainly depends on the nose-shape, and the drag force depends on tunnel existence. Also. a push -pull (i.e.impluse force) force successively acts on each car and acts in different directions between the neighborhood cars. The maximum change of the impulsive force reaches about 3 tons. These aerodynamic force data are absolutely necessary to evaluate the stability of high speed multi-car trains. The results also indicate the effectiveness of the present numerical method for simulating the unsteady flow fields induced by bodies in relative motion.

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Three-dimensional, conservative, Euler computations using patched grid systems and explicit methods

Cited by 19 publications

References 6 publications

Two-dimensional Euler computations on a triangular mesh using an upwind, finite-volume scheme

Two-dimensional Euler computations on a triangular mesh using an upwind, finite-volume scheme

Algebraic grid generation for complex geometries

Unsteady aerodynamic loads on high speed trains passing by each other

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