Riblets in a turbulent adverse-pressure gradient boundary layer
Riblets in a turbulent adverse-pressure gradient boundary layer
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DOI：
10.2514/6.2010-4706
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发表时间：
2010-06
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影响因子：
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通讯作者：
Stephan KlumppThomas Guldner;M. Meinke
中科院分区：
文献类型：
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作者：
Stephan KlumppThomas Guldner;M. Meinke
脊状表面是众所周知的，以减少零压力梯度湍流中的摩擦阻力。然而，在有壁面的湍流逆压梯度流动中脊的效率还没有得到澄清。由于压缩机叶片或飞机机翼等技术应用具有大面积的逆压梯度流，因此需要分析正压梯度的影响。因此，三套数值模拟的空间发展的湍流边界层进行。每个集都包含一个洁净墙模拟和一个条纹墙模拟。在第一组模拟中，规定了平均流动方向上的零压力梯度，而在第二组和第三组中，施加了逆压力梯度。虽然在零压力梯度的情况下，与清洁表面相比，沟槽的摩擦阻力的减少与基于初步通道流模拟的预期一样高，即4- 5%，但在第一次测试的逆压力梯度下发现摩擦阻力减少约7-8%。通过两倍高的逆压梯度，减阻量甚至增加到9-10%。
Riblet surfaces are well known to reduce friction drag in zero-pressure gradient turbulent flows. However, the efficiency of riblets in wall-boundedturbulent adverse-pressure gradient flow has not been clarified. Since technical applications, such as compressor blades or aircraft wings possess large regions of adverse-pressure gradient flow the impact of positive pressure gradients is to be analyzed. Therefore, three sets of numerical simulations of a spatially evolving turbulent boundary layer are performed. Each set consists of one clean-wall simulation and one riblet-wall simulation. In the first set of simulations a zeropressure gradient in the mean flow direction is prescribed, whereas in the second and third set adverse-pressure gradients are imposed. While in the zero-pressure gradient case the reduction of friction drag by the riblets compared to the clean surface is as high as expected based on preliminary channel flow simulations, namely 4-5%, a reduction of friction drag of about 7-8% is found at the first tested adverse-pressure gradient. The amount of drag reduction is even increased to 9-10% by a twice as high adverse-pressure gradient.