共查询到17条相似文献,搜索用时 140 毫秒
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在激波区使用自适应壁对跨音速翼型的激波/边界层的相互作用(干扰)进行控制,可改变机翼的气动性能,这种被动控制可通过在翼型的激波区开一凹腔,其上覆盖一弹性橡胶膜柔壁来,本文给出用Navier-Stoker方程数值模拟这一自适应控制翼型的跨音速粘性绕流,提出了一个适应于本特殊情况(物面边界局部地区在求解过程中有变化)的处理办法。并探讨了自适应柔壁对当代跨音速翼绕流的影响。 相似文献
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大型低速二元风洞侧壁边界层控制及对单段翼型实验结果的影响 总被引:1,自引:0,他引:1
本文简述了NF-3风洞二元实验段侧壁边界层吹除控制系统及具有吹气的模型实验方法,给出了不同吹气系数对风洞边界层的控制效果以及对相对厚度为7%的单段翼型实验结果的影响。初步实验研究结果表明,该控制系统能有效地改善风洞侧壁边界层的流动状态,减小侧壁干扰,改善翼型实验中的二元流动特性 相似文献
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低湍流度风洞中湍流度对平板边界层转捩影响的试验研究 总被引:2,自引:0,他引:2
本文报告了在西北工业大学壁低流度风洞中进行了平板边界层转捩试验研究的简况及初步结果,试验湍流度为0.02%、0.1%及0.33%,用恒温热线风速仪测量时均速度型,求得边界层沿流向的位移厚度分布,并用示波器观察速度脉动脉形变化,从而确定起始转捩点和完全转捩点位置。结果表明,转捩的规律性和国外经典结果极为吻合。 相似文献
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流体力振动翼型和襟翼的绕流特性研究…李锋超薄膜磁头滑块气动力特性............……饱和非饱和土壤中溶质运移的数值模拟……半浮区液桥热毛细对流速度场特征.....……浮体直棱角附近流场的奇异性.........……后向台阶湍流拟序结构的实验研究.....……Y型柱体绕流特性及风荷载.........……,…崔尔杰征宁孙秦学王保育汪翼云.....……傅仙罗邱克俭戚隆溪解京昌唐泽眉....……朱林生胡文瑞戴遗山连淇祥顾志福低超声速圆球绕流后体流场的数值模拟……昊应湘扰动本构方程及粘弹流体拉伸流动不稳定性...……高速二元柔壁自适应风洞消除三元… 相似文献
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H.-J. Romberg 《Experiments in fluids》1990,9(3):177-180
To demonstrate the flow quality of the AIA transonic windtunnel, the flow around a supercritical airfoil is investigated in the adaptive wall test section. The mechanism of the wall adaption is described. The convergence of one adaption cycle is shown by means of the wall contours as well as the wing surface pressures. The shape and pressure distribution of the adapted wall is compared with results obtained in the ONERA T2 windtunnel in Toulouse. That tunnel is equipped with an adaptive wall test section of nearly the same geometry. 相似文献
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B. L. Medved 《Experiments in fluids》1993,15(6):401-410
An experimental investigation of the static pressure fluctuation generation mechanism was performed for different transonic wind tunnel test section perforated wall configurations. Different hole diameters and geometrical configurations were investigated. Most tests were carried out with isolated perforations, while some were done with a three hole, 16° perforation pattern. To suppress the oscillation amplitudes generated by perforations, splitter-plates as flow conditioning devices along the perforations were implemented on a large number of perforated transonic test section wall samples. It was found that all the hole configurations tested, regardless of diameter or shape, resonate at discrete frequencies which order themselves along several modes. 相似文献
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In this paper we study the validation of the new formulation (potential-stream vector) of the steady Euler equations in 2-D/3-D transonic lifting regime flow. This approach, which is based on the Helmholtz decomposition of a velocity vector field, is designed to extend the potential approximation of Euler equations for severe situations such as high transonic or rotational subsonic flows. Different results computed by a fixed point algorithm on the stream vector correction are shown and discussed by comparing them with those obtained by the full potential approach. 相似文献
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The aeroelastic behavior of wing models is nonlinear particularly in the transonic speed range. The interaction between aerodynamic and structural forces can lead to the occurrence of Limit-Cycle Oscillations (LCOs). If in addition the wing model is flexible and backward swept, the kinematic coupling between bending and torsion makes the situation even more complex.In the research project “Aerostabil” such a wing was investigated, which was equipped with pressure transducers in three sections and accelerometers. The experiments were performed in the adaptive test section of the transonic wind tunnel TWG in Göttingen. Already Dietz et al. (2003) have reported about experimental details and preliminary results. Based on these data Bendiksen (2008) studied numerically LCO-flutter behavior using a very similar, theoretical model (G-wing) and Stickan et al. (2014) used the original data as a LCO flutter test case. The influence of flexibility on the steady aerodynamics of the wing was described in Schewe & Mai (2018). In this paper now the flutter experiments with the same flexible model were analyzed systematically in the transonic range 0.84 <Ma <0.89 and for six angles of attack from 1.46°to 2.7°. Maps of stability, LCO amplitudes and instantaneous pressure distributions are presented. It was found that unstable regions are islands, whose extent depends on the angle of attack. A LCO test case, already treated in the literature is examined in more detail. The analysis of the time functions showed that during LCO-flutter the motion induced aerodynamic sectional lift forces particularly in the outer wing are asymmetric and thus acting as amplitude limiter. The reason for the asymmetry lies in the shock/boundary layer interaction. The test case, containing the stages of built-up and the transition to the limit cycle provides an excellent opportunity for improving our knowledge about LCOs and for code validation purposes. 相似文献
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On Methods of Experimental Investigation of the Laminar-Turbulent Transition at Transonic Velocities
The results of an experimental investigation of the laminar-turbulent transition on a flat plate at transonic velocities, performed in a transonic wind tunnel, are presented. A comparative analysis of the transition data obtained by various methods is given. 相似文献
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G. Zuppardi 《Experiments in fluids》2001,31(2):202-207
The present work reports some experimental results from the adaptive walls wind tunnel in Naples and must be considered a
logical step forward in validating the wall adaptation process of this tunnel. Two sets of new tests were made for evaluating
the effects of wall adaptation: one on the location of laminar–turbulent transition and turbulent separation points, the other
one on the measurement of aerodynamic forces and moments, taken by a strain gage balance. Up to now, aerodynamic forces and
moments were evaluated by the integration of pressure distributions on the model surface. All results agree with the theory,
and measurement of aerodynamic forces has also been partially validated. Using a balance proved to be a technical shortcoming
in the testing device.
Received: 5 September 2000/Accepted: 25 January 2001 相似文献
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为抑制跨超声速风洞扩散段的分离,提出了一种较为完备的设计方法。由于影响扩散段性能的参数较多,完全通过试验方法进行设计的成本过高,该方法通过数值模拟,结合适当的边界条件,详细描述了扩散段角度、分流锥角度与长度、孔板开孔率对扩散段性能的影响;从数值模拟的结果可以看出,孔板开孔率和扩开角对扩散段性能有显著影响,通过比较得出较为合理的参数匹配,提高了扩散段的防分离性能,并改善了出口气流质量。数值结果与试验结果结论一致,表明本文所用的方法用于扩散段气动设计是可行的,为数值模拟方法应用于风洞部段气动设计创造了一定的条件。 相似文献