{"title":"NACA4412地内效应的形状优化-湍流模型的选择","authors":"N. JithinP., Ajith Kumar Arumugham-Achari","doi":"10.1115/fedsm2021-65600","DOIUrl":null,"url":null,"abstract":"\n Shape optimisation of a wing-in-ground airfoil would be required to improve its aerodynamic characteristics under various flight conditions. Identification of an optimised shape at various heights above ground (h/c) and angles of attack (α) could be helpful in developing morphing wing capabilities for such airfoil. Prior to conducting shape optimisation a suitable turbulence model have to be selected for such studies. We have performed In-ground-effect (IGE) simulations using four turbulence models, viz., Spalart Allmaras, SST k-ω, Standard k-ε and Transition SST model, to compare their advantages and disadvantages during such analysis. For an unaltered NACA4412 airfoil, while all the models predicted coefficient of lift (Cl) in close agreement with experimental results, Transition SST model was able to predict fine details like laminar separation bubble formation. There was a generic discrepancy in predicting drag coefficients (Cd) with all these turbulence models. However results from Transition SST were the closest to experiments. Spalart Allmaras and SST k-ω were better in the prediction of Cd when compared to standard k-ε model. We consider such studies would be helpful to generate a database of optimised airfoils for a variety of flight conditions near to ground.","PeriodicalId":359619,"journal":{"name":"Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics","volume":"41 1","pages":"0"},"PeriodicalIF":0.0000,"publicationDate":"2021-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Shape Optimisation of NACA4412 In-Ground Effect- Selection of a Turbulence Model\",\"authors\":\"N. JithinP., Ajith Kumar Arumugham-Achari\",\"doi\":\"10.1115/fedsm2021-65600\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"\\n Shape optimisation of a wing-in-ground airfoil would be required to improve its aerodynamic characteristics under various flight conditions. Identification of an optimised shape at various heights above ground (h/c) and angles of attack (α) could be helpful in developing morphing wing capabilities for such airfoil. Prior to conducting shape optimisation a suitable turbulence model have to be selected for such studies. We have performed In-ground-effect (IGE) simulations using four turbulence models, viz., Spalart Allmaras, SST k-ω, Standard k-ε and Transition SST model, to compare their advantages and disadvantages during such analysis. For an unaltered NACA4412 airfoil, while all the models predicted coefficient of lift (Cl) in close agreement with experimental results, Transition SST model was able to predict fine details like laminar separation bubble formation. There was a generic discrepancy in predicting drag coefficients (Cd) with all these turbulence models. However results from Transition SST were the closest to experiments. Spalart Allmaras and SST k-ω were better in the prediction of Cd when compared to standard k-ε model. We consider such studies would be helpful to generate a database of optimised airfoils for a variety of flight conditions near to ground.\",\"PeriodicalId\":359619,\"journal\":{\"name\":\"Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics\",\"volume\":\"41 1\",\"pages\":\"0\"},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2021-08-10\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1115/fedsm2021-65600\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Volume 1: Aerospace Engineering Division Joint Track; Computational Fluid Dynamics","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1115/fedsm2021-65600","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 0
摘要
机翼在地面翼型的形状优化将需要改善其在各种飞行条件下的空气动力学特性。识别一个优化的形状在不同高度的地面(h/c)和迎角(α)可能有助于发展这种翼型的变形翼能力。在进行形状优化之前,必须为此类研究选择合适的湍流模型。我们使用四种湍流模型(Spalart Allmaras, SST k-ω, Standard k-ε和Transition SST模型)进行了地内效应(IGE)模拟,比较了它们在这种分析中的优缺点。对于一个不变的NACA4412翼型,而所有的模型预测升力系数(Cl)与实验结果密切一致,过渡SST模型能够预测精细的细节,如层流分离气泡的形成。这些湍流模型在预测阻力系数(Cd)方面存在普遍差异。然而,Transition SST的结果与实验最接近。与标准k-ε模型相比,Spalart Allmaras和SST k-ω对Cd的预测效果更好。我们认为这样的研究将有助于产生一个数据库的优化翼型的各种飞行条件接近地面。
Shape Optimisation of NACA4412 In-Ground Effect- Selection of a Turbulence Model
Shape optimisation of a wing-in-ground airfoil would be required to improve its aerodynamic characteristics under various flight conditions. Identification of an optimised shape at various heights above ground (h/c) and angles of attack (α) could be helpful in developing morphing wing capabilities for such airfoil. Prior to conducting shape optimisation a suitable turbulence model have to be selected for such studies. We have performed In-ground-effect (IGE) simulations using four turbulence models, viz., Spalart Allmaras, SST k-ω, Standard k-ε and Transition SST model, to compare their advantages and disadvantages during such analysis. For an unaltered NACA4412 airfoil, while all the models predicted coefficient of lift (Cl) in close agreement with experimental results, Transition SST model was able to predict fine details like laminar separation bubble formation. There was a generic discrepancy in predicting drag coefficients (Cd) with all these turbulence models. However results from Transition SST were the closest to experiments. Spalart Allmaras and SST k-ω were better in the prediction of Cd when compared to standard k-ε model. We consider such studies would be helpful to generate a database of optimised airfoils for a variety of flight conditions near to ground.