CFD model

RIAM-COMPACT

WindSim

Turbulence model

Standard Smagorinsky LES

RNG k-ε RANS

Atmospheric stratification

(Atmospheric stability)

Neutral atmosphere

Coriolis force

Not considered

Surface roughness

Not considered

(Smooth surface)

Roughness length: 0.001

Ground surface

boundary condition

Non-slip condition

(Three wind velocity components at the ground surface are zero.)

Wall function

Shape function of the isolated hill z (r)

0.5h × {1 + cos(πr/a)}, r = (x² + y²)^1/2, a = 2h

Height of the isolated hill h

100 (m)

Reynolds number Re (=U_inh/ν)

5 × 10⁴ and 1 × 10⁷

5 × 10⁴ and 1 × 10⁷

Time step Δt

10⁻³ h/U_in (s) for Re = 5 × 10⁴

10⁻⁷ h/U_in (s) for Re = 1 × 10⁷

-

Computational domain size

13h (i) × 9h (j) × 8h (k)

for Re = 5 × 10⁴

13h (i) × 9h (j) × 8h (k)

19h (i) × 18h (j) × 8h (k)

for Re = 1 × 10⁷

Number of computational grid points

325 (i) × 226 (j) × 37 (k)

(Approx. 2.7 million points)

for Re = 5 × 10⁴

325 (i) × 226 (j) × 37 (k)

(Approx. 2.7 million points)

436 (i) × 325 (j) × 101 (k)

(Approx. 14.3 million points)

for Re = 1 × 10⁷

Streamwise (x) grid spacing (Δx)

0.04 × h for Re = 5 × 10⁴

(0.035 - 0.5) × h for Re = 1 × 10⁷

0.04 × h

Spanwise (y) grid spacing (Δy)

Vertical (z) grid spacing (Δz)

(0.05 - 0.40) × h for Re = 5 × 10⁴

(0.000004 - 0.6) × h for Re = 1 × 10⁷

(0.05 - 0.40) × h