Simultaneous measurement of velocity and pressure in a plane jet
Simultaneous measurement of velocity and pressure in a plane jet
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同时测量平面射流中的速度和压力
DOI：
10.1007/s00348-012-1351-z
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发表时间：
2012
影响因子：
2.4
通讯作者：
Kouji NAGATA
中科院分区：
文献类型：
--
作者：
Osamu TERASHIMA;Yasuhiko SAKAI;Kouji NAGATA
开发了一种同时测量湍流中的速度和压力的新技术。为了实现这一目标，开发了一种由 X 型热线探头和新设计的压力探头组成的新型探头（以下称为组合探头）。压力探头通过 MEMS 制造工艺并使用 0.1 英寸的传感器进行了小型化。麦克风作为压力传感器，用于提高空间分辨率。将该压力探头放置在构成X型热线探头的两个热线传感器之间。压力探头采用半球形尖端，类似于皮托管，因为早期带有锥形尖端的压力探头会降低空间分辨率。组合探头的压力探头和热线探头的空间布置是经过仔细确定的，因为当两个探头放置得非常接近时，存在一个探头的测量精度会受到另一个探头引起的干扰的影响的风险。因此，组合探头被布置为在由它们各自的探头测量的速度数据和压力数据之间不产生明显的干扰。作为这种组合探头的应用之一，在平面射流中同时测量压力和瞬时速度的两个分量。估计了平面射流间歇区域的湍流能量收支以及速度和压力的互相关系数。结果表明，平均流向速度、速度波动和压力波动曲线与使用X型热线探头或压力探头单独测量的结果一致。此外，结果表明，湍流能量传输方程中扩散项的积分值（理论上应等于0）比以前的报道更接近于0（Bradbury in J Fluid Mech 23（Part 1）：31-64，1965）。此外，间歇区域互相关系数的时间变化支持了先前研究中预测的涡结构模型（Browne et al. in J Fluid Mech 149:355–373, 1984；Tanaka et al. JSME Int J Ser B 49(4):899–905, 2006；Sakai et al. J Fluid Sci Technol 2(3):611–622, 2007)。
A new technique was developed for the simultaneous measurement of velocity and pressure in turbulent flows. To accomplish this objective, a new probe (hereafter called the combined probe) that consists of an X-type hot-wire probe and a newly devised pressure probe was developed. The pressure probe was miniaturized by the MEMS fabrication process and by using a 0.1-in. microphone as a pressure sensor for improving the spatial resolution. This pressure probe was placed between two hot-wire sensors of which the X-type hot-wire probe was composed. The pressure probe was given a hemispherical tip, like that of a pitot tube, because an earlier pressure probe with a conical tip suffered from a reduction in spatial resolution. The spatial arrangement of the pressure probe and the hot-wire probe for the combined probe was carefully determined, because there was a risk that the measurement accuracy of one probe will be influenced by disturbances caused by the other probe when the two probes were placed very close to each other. Therefore, the combined probe was arranged to engender no noticeable interference between the velocity data and the pressure data measured by their respective probes. As one application of this combined probe, simultaneous measurements of pressure and two components of instantaneous velocity were performed in a plane jet. The turbulent energy budget and the cross-correlation coefficient of velocity and pressure in the intermittent region of the plane jet were estimated. The results show that the mean streamwise velocity, velocity fluctuation, and pressure fluctuation profiles were consistent with those measured individually using the X-type hot-wire probe or pressure probe. Moreover, it was shown that the integral value of the diffusion term (which should theoretically be equal to zero) in the turbulent energy transport equation was closer to zero than previous reports (Bradbury in J Fluid Mech 23(Part 1):31–64, 1965). In addition, the time variation of the cross-correlation coefficient in the intermittent region supports the vortex structure model predicted in previous studies (Browne et al. in J Fluid Mech 149:355–373, 1984; Tanaka et al. JSME Int J Ser B 49(4):899–905, 2006; Sakai et al. J Fluid Sci Technol 2(3):611–622, 2007).