fluent講義ppt課件-資料下載頁
2025-01-19 19:20本頁面
【正文】 er Law Scheme ? more accurate than firstorder for flows when Recell 5 (typ. low Re flows). ? SecondOrder Upwind Scheme ? uses larger ‘stencil’ for 2nd order accuracy, essential with tri/tet mesh or when flow is not aligned with grid。 slower convergence ? Quadratic Upwind Interpolation (QUICK) ? applies to quad/hex and hyrbid meshes (not applied to tri’s), useful for rotating/swirling flows, 3rd order accurate on uniform mesh. 7/5/2022 39 CFDFVM PressureVelocity Coupling ? SIMPLE ? default scheme, robust ? SIMPLEC ? Allows faster convergence for simple problems (., laminar flows with no physical models employed). ? PISO ? useful for unsteady flow problems or for meshes containing cells with higher than average skew. 7/5/2022 40 CFDFVM FLUENT interpolation schemes for Face Pressure: ? Standard ? default scheme。 reduced accuracy for flows exhibiting large surfacenormal pressure gradients near boundaries. ? Linear ? use when other options result in convergence difficulties or unphysical behavior. ? SecondOrder ? use for pressible flows。 not to be used with porous media, jump, fans, etc. or VOF/Mixture multiphase models. ? Body Force Weighted ? use when body forces are large, ., high Ra natural convection or highly swirling flows. ? PRESTO! ? use on highly swirling flows, flows involving porous media, or strongly curved domains. 7/5/2022 41 CFDFVM ?得到可靠的 CFD數(shù)據(jù) (對(duì) fluent而言 ) ? 正確選擇物理模型和邊界條件 ? 高質(zhì)量的網(wǎng)格 ?一般縱高比不超過 5： 1（除邊界層網(wǎng)格外） ?相鄰網(wǎng)格的 grading最好不要超過 7/5/2022 42 CFDFVM ?提高精度： ? 采用 2階離散格式 ? 確定解是不依賴于網(wǎng)格的 采用自適應(yīng)網(wǎng)格來改進(jìn)網(wǎng)格 Original mesh Mesh after pressure gradient adaption 7/5/2022 43 CFDFVM ?任何 CFD計(jì)算結(jié)果都要進(jìn)行檢驗(yàn) ? 應(yīng)用計(jì)算流體力學(xué)理論 ? 應(yīng)用實(shí)驗(yàn)數(shù)據(jù) ? 其他 CFD數(shù)據(jù) ?高質(zhì)量的 CFD模擬結(jié)果是建立在對(duì)流體機(jī)理的正確理解 7/5/2022 44 CFDFVM 參考 1. 流體中文網(wǎng)： 2. 傲雪論壇： 3. 清華大學(xué) BBS 4. 北京?；? 5. Fluent 幫助文件
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