Test Case

Brief Description of the Study Test Case

The case considered is the flow past a finite-height circular cylinder mounted on a flat plate for two height-to-diameter ratios h/D = 2.5 and 5.0. The parameters of the study and the dimensions of the cylinder are given in Table 1. The cylinder was placed in a water tunnel and the measurement section dimensions are provided in Fig. 2. The thickness of the approach- flow boundary layer was about 0.1 = h and the free-stream turbulence level was Tu ≈ 2%.

Figure 2. Experimental configuration for flow visualization and LDV measurements, from Palau-Salvador et al (2010)

Test Case Experiments

The experiments were carried out by Kappler (2002) in the closed high pressure water tunnel of the Institute for Hydromechanics at the University of Karlsruhe. The experiments are described in detail in Kappler (2002) and a link to the actual data is given in the reference. A short description is provided in Palau-Salvador et al (2010). The measurement section and the cylinder placed in it are shown in Fig. 2. Measurements of all three components of mean and fluctuating velocities were carried out with a 2D LDV in two consecutive steps. In the first step, the optical axis was oriented in the vertical direction, thus allowing determination of the velocity components u and v. In the second step, the optical system was reconfigured to point horizontally for simultaneous measurements of u and w (see also Fig. 2). The uncertainty in the velocity measurements was judged to be less than 5% of the inlet velocity for the mean and fluctuation values, with somewhat higher possible errors for the turbulent shear stress. Reference LDV measurements were performed without the cylinder in place in order to determine the boundary layer characteristics at different streamwise positions and the results are included in Kappler (2002). Prior to the LDV measurements, extensive flow visualizations were carried out for four cylinder configurations in the range h/D = 2.0 – 5.0. The results can also be found in Kappler (2002).

In addition to the components of mean and fluctuating velocities measured in various vertical and horizontal planes, and the visualizations of Kappler with dye-injection, some oil flow pictures showing the streamlines of the flow near the ground, along the cylinder walls and also the complex flow at the top of the cylinder are available from other studies at h/D = 2. Some of these results and the original references are included in Palau Salvador et al (2010).