Name: Turbulent Bump validation
Creator: FlowDeck
License: https://creativecommons.org/licenses/by/4.0/

Validation: 2D Coupled Lattice Boltzmann and Finite Difference, Turbulent Flow, Turbulent transport

Description

Turbulent, flow over a symmetric bump shape in 2D. A uniform free stream enters at the inlet and runs over a symmetry (slip) section before reaching the no-slip bump, where the boundary layer develops from the leading edge. A final symmetry section extends from the end of the bump to the outlet.

The wall is modelled with a wall function and the slip sections use a symmetry boundary. The top boundary is zero gradient and the outlet is an outlet condition. Eddy viscosity is set as 0.0 at the inlet and zero gradient on all other boundaries. The wall eddy viscosity is set using the wall function.

Figure 1: Flow domain

Simulation Inputs

Input	Value
Material Properties	Density = 1.0 kg/m³, Viscosity = 2.29 × 10⁻⁵ m²/s.
Geometry	L = 1.5m, H = 1.3m. Bump geometry: $y (x) = 0.05 \cdot \sin (x π \frac{10}{9} - \frac{π}{3})$ for 0.3 < x < 1.2, y(x) = 0.0 for x < 0.3, x > 1.2.
Boundary Conditions	Inlet uniform velocity U_∞ = 68.6 m/s. Reynolds number = 1.0*U_∞/v = 3.0 × 10⁶.

Assumptions and Notes

Flow is steady and incompressible.

Results

Velocity magnitude over the bump — Figure 2: Velocity magnitude

Skin friction vs CFL3D

Hover or tap the chart to read the values at any point. Click a legend item to show or hide it. Table values are interpolated to each station; the chart and CSV have the full distributions.

Figure 3: Skin friction vs CFL3D

Skin friction along the wall: CFL3D vs FlowDeck, every 0.05 m

x (m)	CFL3D C_f	FlowDeck C_f
0.05	0.00434	0.00466
0.10	0.00396	0.00423
0.15	0.00370	0.00394
0.20	0.00350	0.00369
0.25	0.00330	0.00347
0.30	0.00309	0.00325
0.35	0.00279	0.00298
0.40	0.00250	0.00265
0.45	0.00243	0.00253
0.50	0.00272	0.00268
0.55	0.00340	0.00316
0.60	0.00443	0.00412
0.65	0.00559	0.00516
0.70	0.00637	0.00604
0.75	0.00615	0.00593
0.80	0.00487	0.00476
0.85	0.00320	0.00319
0.90	0.00192	0.00199
0.95	0.00127	0.00131
1.00	0.00114	0.00111
1.05	0.00135	0.00122
1.10	0.00173	0.00154
1.15	0.00211	0.00198
1.20	0.00235	0.00223
1.25	0.00247	0.00238
1.30	0.00255	0.00248
1.35	0.00259	0.00255
1.40	0.00262	0.00261
1.45	0.00265	0.00266

Velocity profile at x = 0.75 and 1.2 vs CFL3D

Hover or tap the chart to read the values at any point. Click a legend item to show or hide it. CFL3D values in the table are interpolated to the FlowDeck heights.

Figure 4: Velocity profile at x = 0.75, 1.2 vs CFL3D

Velocity profiles at the FlowDeck points: FlowDeck vs CFL3D

z (m)	x (m)	FlowDeck u/U∞	CFL3D u/U∞
0.00080	0.75	0.9187	0.9717
0.00174	0.75	1.0638	1.0871
0.00267	0.75	1.1317	1.1475
0.00360	0.75	1.1729	1.1849
0.00453	0.75	1.2018	1.2105
0.00546	0.75	1.2229	1.2293
0.00640	0.75	1.2389	1.2436
0.00733	0.75	1.2516	1.2547
0.00826	0.75	1.2614	1.2629
0.00919	0.75	1.2683	1.2681
0.01013	0.75	1.2722	1.2701
0.01059	0.75	1.2736	1.2696
0.01246	0.75	1.2717	1.2639
0.01432	0.75	1.2658	1.2591
0.01618	0.75	1.2609	1.2545
0.01805	0.75	1.2566	1.2500
0.01991	0.75	1.2522	1.2456
0.02178	0.75	1.2479	1.2414
0.02364	0.75	1.2437	1.2372
0.02551	0.75	1.2397	1.2331
0.02737	0.75	1.2357	1.2292
0.02923	0.75	1.2319	1.2253
0.03017	0.75	1.2301	1.2234
0.03390	0.75	1.2229	1.2160
0.03762	0.75	1.2159	1.2090
0.04135	0.75	1.2092	1.2023
0.04508	0.75	1.2029	1.1959
0.04881	0.75	1.1968	1.1898
0.05254	0.75	1.1910	1.1840
0.05627	0.75	1.1854	1.1784
0.00047	1.2	0.4756	0.4979
0.00140	1.2	0.5753	0.5856
0.00233	1.2	0.6159	0.6272
0.00326	1.2	0.6432	0.6567
0.00419	1.2	0.6658	0.6812
0.00513	1.2	0.6862	0.7031
0.00606	1.2	0.7055	0.7237
0.00699	1.2	0.7241	0.7434
0.00792	1.2	0.7424	0.7625
0.00886	1.2	0.7606	0.7812
0.00979	1.2	0.7787	0.7995
0.01025	1.2	0.7874	0.8085
0.01212	1.2	0.8234	0.8433
0.01398	1.2	0.8592	0.8756
0.01585	1.2	0.8943	0.9044
0.01771	1.2	0.9274	0.9285
0.01958	1.2	0.9542	0.9464
0.02144	1.2	0.9691	0.9568
0.02330	1.2	0.9733	0.9602
0.02517	1.2	0.9738	0.9607
0.02703	1.2	0.9740	0.9609
0.02797	1.2	0.9745	0.9610
0.02890	1.2	0.9745	0.9611
0.03076	1.2	0.9750	0.9614
0.03169	1.2	0.9753	0.9615
0.03542	1.2	0.9757	0.9619
0.03915	1.2	0.9759	0.9624
0.04288	1.2	0.9766	0.9629
0.04661	1.2	0.9773	0.9634
0.05034	1.2	0.9778	0.9639

Reference Data

Skin friction and velocity profiles are compared against numerical CFL3D results from the NASA TMR turbulent bump case [1].

References

Turbulent Modelling Resource, Bump, https://tmbwg.github.io/turbmodels/.

Data licence. The model results on this page and in the CSV downloads are published by FlowDeck under the Creative Commons Attribution 4.0 licence (CC BY 4.0). The reference values are from the sources listed under References.