Simulation of the turbulent flow in a 3D channel and over a surface

mounted cube

Youngwook Kang, Cornell University

Andrei Simion, The Cooper Union

Svetlana V. Poroseva, CSIT, Florida State University

Objectives

• To become proficient in using Fluent and Gambit

• To get experience in:

1. acquiring numerical solutions of PDE

2. solving a CFD problem

Problem Description

Study on the influence of different side wall boundary conditions on flow characteristics in a 3D geometry.

- Flow types 1. Flow in a rectangular channel 2. Flow over a surface mounted cube

- Boundary Conditions 1. Periodic 2. Solid

• Channel Geometry: 2h in height, 2h in flow direction, and 3h in spanwise direction. (h=0.025m)

• Channel with surface mounted cube:

• Fluid: air

Data from Hussain and Marinuzzi’s experiment (1996) was used.

800002

Re hUb

Flow Geometry

smS

UdSUb /37.23

Turbulence Models

T

jj

k

T

T

k

kC

k

PC

tD

D

xU

tD

DkP

tD

kD

kC

CCC

k

2

21

2

21

/

3.1 0.1 92.1 44.1 09.0

:model

itymean veloc - raten dissipatio -

energy kinetic -

iU

k

Numerical Procedure - 2nd order spatial discretization scheme - Segregated, implicit solver

- Steady flow - Boundary Conditions 1. Walls in z direction 2. Walls/Periodic in x direction 3. Channel: Periodic inlet/outlet 4. Cube: Fully developed channel flow (inlet) and convective outlet

Grid - Structured non-uniform with clustering near walls

- With such grid resolution, wall description with wall functions; focus on mean velocity profiles.

Channel (x:z) 47:41

Cube (x:z:y) 47:41:86

Channel Plots

Channel Plots (cont.)

Surface Mounted Cube Plots

Surface Mounted Cube Plots (cont.)

Surface Mounted Cube Plots (cont.)

Contours

Contours (cont.)

Results and Conclusion

• We have learned how to use Fluent and Gambit to design simple meshes and solve CFD problems in application to turbulence modeling.

• Different boundary conditions on side walls have a great influence on the flow characteristics, such as velocity, vorticity, and turbulent kinetic energy.