کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5012089 1462672 2016 35 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Improving finite-volume diffusive fluxes through better reconstruction
ترجمه فارسی عنوان
بهبود فواصل پخش محدود حجم از طریق بازسازی بهتر
کلمات کلیدی
شار دیفرانسیل، بازسازی حداقل مربعات، مش ساختار نشده روش های مرتب بالا، روشهای محدود حجم، دینامیک سیالات محاسباتی،
موضوعات مرتبط
مهندسی و علوم پایه سایر رشته های مهندسی مکانیک محاسباتی
چکیده انگلیسی
The overarching goal of CFD is to compute solutions with low numerical error. For finite-volume schemes, this error originates as error in the flux integral. For diffusion problems on unstructured meshes, the diffusive flux (computed from reconstructed gradients) is one order less accurate than the reconstructed solution. Worse, the gradient errors are not smooth, and so no error cancellation accompanies the flux integration, reducing the flux integral to zero order for the second-order schemes. Our aim is to compute the gradient and flux more accurately at the cell boundaries and hence obtain a better flux integral for a slight increase in computational cost. We propose a novel reconstruction method and flux discretization to improve diffusive flux accuracy on cell-centered, isotropic unstructured meshes. Our approach uses a modified least-squares system to reconstruct the solution to second-order accuracy in the H1 norm instead of the prevalent L2 norm, thus ensuring second-order accurate gradients. Either circumcenters or containment centers are chosen as the control-volume reference points based on a criteria to facilitate calculation of second-order gradients at flux quadrature points using a linear interpolation scheme along with a high-accuracy jump term to enhance stability of the system. Numerical results show a significant improvement in the order of accuracy of the computed diffusive flux as well as the flux integral. When applied to a channel flow advection-diffusion problem, the scheme resulted in an increased order of accuracy for the flux integral along with gains in solution accuracy by a factor of two. Similar gains in solution accuracy are also seen when applied to an incompressible Navier-Stokes problem.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Computers & Fluids - Volume 139, 5 November 2016, Pages 216-232
نویسندگان
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