共查询到20条相似文献,搜索用时 93 毫秒
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三角形沟槽表面流场的数值模拟 总被引:1,自引:0,他引:1
湍流阻力在流体运输、航空和航海等领域广泛存在,是管道、常规运输机、水上船只、潜艇和机翼等与粘性流体接触的工作部件的主要能耗来源.文章利用有限体积法对26种三角形仿生非光滑沟槽表面流场进行了数值计算.近壁面区采用B-L两层模型,外区采用雷诺应力模型.通过与油槽实验数据定性对比,验证了数值模拟沟槽非光滑表面减阻的精度及可靠性,为软件模拟非光滑壁面流场提供依据.同时还对7种压力梯度下沟槽表面流场进行模拟,研究了压力梯度对减阻效果的影响. 相似文献
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沟槽面减阻效果影响因素及减阻机理的分析 总被引:1,自引:0,他引:1
采用雷诺平均N-S方程和RNG k-ε湍流模型计算V型沟槽面的湍流边界层流动和粘性阻力,研究了沟槽尖峰形状和雷诺数对减阻效果的影响规律,初步分析了沟槽面减阻机理.指出:沟槽尖峰处的圆角半径越小其减阻效果越好,沟槽斜面中下部的壁面应力随着圆角半径的减小而降低,但尖峰处的局部壁面应力会随之增大;来流速度对沟槽减阻率的影响很大,对于一种尺度的V型沟槽,存在着一个具有较好减阻效果的来流速度范围,而沟槽面在沿来流方向上的布置位置对减阻效果的影响非常小;沟槽尺度对减阻效果很剧烈;沟槽尖峰处生成的二次涡是产生减阻效果的根本原因,二次涡的强弱与沟槽减阻率的大小紧密相关. 相似文献
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[Objectives]Flow separation increases the drag and noise of underwater vehicles, and influences the controllability of their control surfaces. Therefore, the influence of slip caused by superhydrophobic surfaces on drag reduction and flow separation is studied. [Methods]A partial slip boundary condition is developed, and the flow around a circular cylinder and foil with a slip boundary at high Reynolds numbers are numerically simulated. [Results]The results show that the when the slip length increases, the flow around the cylinder goes through three stages: the turbulent Kármán vortex street, laminar Kármán vortex street and non-separation Stokes flow. The drag coefficient increases first and then decreases, and the vortex shedding frequency increases. For flow around a foil, the separation position moves downstream until the separation region disappears when the slip length increases, and the drag coefficient decreases while the lift coefficient increases. [Conclusions]The results of this study show that for flow past bluff body at high Reynolds number, the slip boundary can control flow separation and reduce drag effectively, providing technical support for the application of superhydrophobic surfaces for the flow control of underwater vehicle appendages. © 2022 Journal of Clinical Hepatology. All rights reserved. 相似文献
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排气管内二维非定常流动的计算研究 总被引:2,自引:0,他引:2
为了优化设计排气管形状,本文研究了柴油机排气管内二维非定常湍流流动的计算,排气管与气缸交接处的边界条件由实验结出,湍流模型采用k-ε模型。计算了一根3缸模型排气管内排气流动变化,计算结果与实验结果吻合良好。该研究对排气管的形状设计有一定的应用价值。 相似文献