弹塑性流体的三阶 WENO 方法及壁热误差的修正

A THIRD-ORDER WENO METHOD FOR ELASTIC-PLASTIC FLOWS AND CORRECTION OF THE WALL-HEATING ERROR

  • 摘要:
    针对弹塑性流体数值模拟中的高阶拉格朗日离散与壁热误差问题,本文基于次弹性
    Wilkins 模型构造单元中心拉格朗日格式。数值流通量由 HLLC 型近似黎曼解法器给出,其中一维情
    形采用含弹性波和塑性波的波结构,二维情形则含弹性纵波、弹性剪切波和接触波。在此基础上,一
    方面依据一维局部波结构修正壁热黏性中的声速选取,兼顾减少局部壁热误差和保持分辨率;另一方
    面将三阶 WENO 重构进一步用于二维非结构拉格朗日四边形网格。数值结果表明,格式在光滑算例
    中达到预期收敛阶,并能较好捕捉典型弹塑性算例的主要波形。

     

    Abstract:
    A cell-centered Lagrangian method is developed for elastic-plastic flows governed by
    the Wilkins hypoelastic model. Its numerical fluxes are obtained from HLLC-type approximate Rie
    mann solvers: the one-dimensional solver retains the elastic and plastic wave structure, while the two
    dimensional solver contains elastic longitudinal, elastic shear and contact waves. Based on the local
    one-dimensional wave classification, the sound speed in the wall-heating viscosity is modified so that the
    added dissipation is better matched with the elastic-plastic wave pattern. This treatment reduces the
    wall-heating error while keeping the resolution of the main wave profiles. A third-order WENO recon
    struction is also applied to two-dimensional unstructured Lagrangian quadrilateral meshes, together with
    a vertex velocity construction based on local momentum balance. Numerical tests show that the method
    attains the expected order of accuracy for smooth problems and captures the principal wave structures
    in typical elastic-plastic examples.

     

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