cases:case069

# Flow over Isolated 2D Hill

The case is flow over an isolated 2D hill in a neutral boundary layer, as shown schematically in figure 1. The free-stream velocity $U_{\infty} = 4$ m/s. Three hill geometries are considered, each with hill height $H = 0.117$ m, but having different aspect ratios $a/H$ of 3, 5 and 8.

Fig. 1: Flow geometry

The shape of the hill is give parametrically for $|\xi| \le a$ by

$x(\xi) = 0.5\xi \left[ 1 + \frac{a^2}{\xi^2 + m^2 (a^2 - \xi^2)} \right]$ $z(\xi) = 0.5m (a^2 - \xi^2)^{1/2} \left[ 1 - \frac{a^2}{\xi^2 + m^2(a^2 - \xi^2)} \right]$

where $m = (H/a) + \left[ (H/a)^{2} + 1 \right]^{1/2}$.

Velocities were measured using hot-wires and corrected by Trombetti et al. (1991).

Profiles are available for the three different aspect ratio hills ($a/H=3$, $5$ and $8$) at a number of $x$-locations. Quantities available include:

• the mean velocity $U$ (in m/s)
• flow angle $\phi$ (in degrees)
• rms fluctuating axial and vertical velocities ($u'$ and $w'$) (in m/s)
• Reynolds shear stress $-\overline{uw}$ (in (m/s)2)

The original experimental data have been smoothed and interpolated to yield the final data provided. The minimum height for interpolation is 0.000157(m) and the maximum is 0.8(m). The smoothing is discussed in detail in Trombetti et al. (1992) and Busuoli et al. (1993).

Sample plots of selected quantities are available.

 Reference case (flat surface channel) epanhils.dat
1. Snyder, W.H., Khurshudyan, L.H., Nekrasov, I.V (1981). Flow and dispersion of pollutant within two-dimensional hills. U.S. Env. Prot. Agcy. Rpt. No. EPA-600/4-81-067. Res. Tri. Pk., NC.
2. Trombetti, F., Martano, P., Tampieri, F. (1991). Data sets for studies of flow and dispersion in complex terrain: I) the RUSHIL wind tunnel experiment (flow data). CNR Technical Report No.1, FISBAT-RT-91/1.
3. Busuoli, M., Trombetti, F., Tampieri, F. (1993). Data sets for studies of flow and dispersion in complex terrain: I) the RUSVAL wind tunnel experiment (flow data). CNR Technical Report No.3, FISBAT-RT-93/1.

Indexed data:

case069 (dbcase, semi_confined_flow)
case069
titleFlow over isolated 2D hill
authorSnyder, Khurshudyan, Nekrasov
year1991
typeEXP
flow_tag2d, separated, surface_mounted_body