**4. Results**

compared the present results with the experimental measurements performed by Jacob et al. [9] and the numerical results performed by Boudet et al. [16], Agawal and Sharma [18], and Jiang et al. [21], respectively. However, it is specified that the present study is performed at *Red =* 28,800, *d =* 0.06 m, and other experiments and the simulations are performed at *Red =* 48,000, *d =* 0.1 m. **Figure 6** shows the mean velocity and RMS value of the fluctuation velocity in *x* (streamwise) direction normalized by the incoming velocity at two locations *x/c =* 0.87 and *x/c =* 0.25. As shown in **Figure 6(a)**, the present calculation predicted similar mean velocity profile in the streamwise direction compared with other numerical results. As shown in **Figure 6(b)**, the RMS value of the fluctuation velocity in the streamwise direction obtained by the present calculation is close to those obtained by the other numerical calculations; however, the difference of the fluctuation velocity near the center-line can be seen. A possible cause for this result is the difference of the methods, meshes and Reynolds number. **Figure 6(c)** and **(d)** shows that the calculated profiles of the mean velocity and the RMS of the fluctuation velocity in the streamwise direction represent a good agreement with those from the experiments

**Figure 7** shows the spectra of the SPL at the location (*x =* 0.68 m, *y =* 1.74 m) calculated by the acoustic BEM simulation using the acoustic sources extracted from the CFD results. The peak frequency (*St* 0.2) and the spectrum around the peak frequency are well predicted compared with the experimental result obtained by Jacob et al. [9]. The peak value of the SPL obtained by the present study is slightly lower than that from the experimental result. There is a difference in the spectrum at high frequencies, *St >* 0.6. A possible cause for these differences of the peak SPL and the spectrum at high frequencies is that the Reynolds number is different between the present study and the experiments, and the mesh and time resolutions for the calculation might not be enough for the accurate prediction of the spectrum at high frequencies. However, the dominant peak SPL and SPLs around the peak frequency are well predicted in the present calculation. The peak frequency *St* 0.2 as shown in **Figure 7** almost corresponds to the vortex shedding frequency of the cylinder [2], which means that the vortex shedding from the rod plays an important

*SPL spectra at the location* x = *0.68 m,* y = *1.74 m. Measured by Jacob et al. [9] (*Red = *48,000);*

role for the noise generation from the rod-airfoil model.

and other numerical results.

*Vortex Dynamics Theories and Applications*

**Figure 7.**

**128**

*present (*Red = *28,800).*
