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Improving the precision of discrete numerical solutions using the generalized integral transform technique
Journal of the Brazilian Society of Mechanical Sciences and Engineering ( IF 1.8 ) Pub Date : 2020-05-24 , DOI: 10.1007/s40430-020-02346-x
Isabela F. Pinheiro , Ricardo D. Santos , Leandro A. Sphaier , Leonardo S. de B. Alves

Most spatial discretizations applied by finite difference and volume methods to advective/convective terms introduce significant diffusive and dispersive numerical errors, where the former is often required to improve the numerical stability to the resulting scheme. This paper presents a new approach that employs integral transforms to improve the accuracy of available discrete numerical solutions. The method uses a known and inaccurate numerical solution to filter the original governing equations, solves the resulting problem using integral transforms, and then uses it to correct the original numerical solution. Before doing so, these numerical solutions are rewritten as a series representation, which is done using the same eigenfunction basis employed by the integral transformation. Different test cases, based on the unsteady and one-dimensional wave motion described by the nonlinear viscous Burgers’ equation in a finite domain, are selected to evaluate the proposed approach. These test cases involve numerical solutions with different types of errors, and are compared with a highly accurate numerical solution for verification. The integral transform technique, in combination with different numerical filters, showed that inaccurate numerical solutions can in fact be corrected by this methodology, as very satisfactory errors were generally obtained. This is true for smooth enough numerical solutions, i.e., the procedure is not advisable to problems that lead to discontinuous numerical solutions.



中文翻译:

使用广义积分变换技术提高离散数值解的精度

通过有限差分和体积方法对对流/对流项应用的大多数空间离散化都会引入明显的扩散和弥散数值误差,其中经常需要使用前者来提高结果格式的数值稳定性。本文提出了一种新方法,该方法采用积分变换来提高可用离散数值解的精度。该方法使用已知且不准确的数值解来过滤原始控制方程,使用积分变换解决所产生的问题,然后将其用于校正原始数值解。在这样做之前,将这些数值解重写为级数表示,这是使用积分变换所使用的相同本征函数基础完成的。不同的测试用例 基于有限域中非线性粘性Burgers方程描述的非定常和一维波动,对方法进行了评估。这些测试用例涉及具有不同类型错误的数值解,并与高精度数值解进行比较以进行验证。积分变换技术与不同的数值滤波器结合使用,表明不精确的数值解实际上可以通过此方法进行校正,因为通常会获得非常令人满意的误差。对于足够平滑的数值解,这是正确的,即,该程序不适用于导致不连续数值解的问题。这些测试用例涉及具有不同类型错误的数值解,并与高精度数值解进行比较以进行验证。积分变换技术与不同的数值滤波器结合使用,表明不精确的数值解实际上可以通过此方法进行校正,因为通常会获得非常令人满意的误差。对于足够平滑的数值解,这是正确的,即,该程序不适用于导致不连续数值解的问题。这些测试用例涉及具有不同类型错误的数值解,并与高精度数值解进行比较以进行验证。积分变换技术与不同的数值滤波器结合使用,表明不精确的数值解实际上可以通过此方法进行校正,因为通常会获得非常令人满意的误差。对于足够平滑的数值解,这是正确的,即,该程序不适用于导致不连续数值解的问题。因为通常会获得非常令人满意的错误。对于足够平滑的数值解,这是正确的,即,该程序不适用于导致不连续数值解的问题。因为通常会获得非常令人满意的错误。对于足够平滑的数值解,这是正确的,即,该程序不适用于导致不连续数值解的问题。

更新日期:2020-05-24
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