CFD simulation of a NACA airfoil – Geometry making, meshing, processing and post processing

Geometry

The geometry consists of multiple joined parts that I will use later to refine the mesh in certain areas. You can download the geometry here – Download.

The total length of the fluid domain is approximately 14.1 m with a maximum width of 5.3 m. Moreover, the chord length of the airfoil is 0.76 m and the maximum thickness is 0.09m. I uploaded a picture of the whole 2D model:

NACA airfoil CFD geometry
NACA airfoil CFD geometry



I dissected the fluid domain into 3 major parts. The first part which is the outer domain has the biggest size cells. The second part, the middle zone, has relatively smaller size cell than the first part. Finally, the inner domain with the smallest mesh cell size.

 

NACA airfoil geometry parts
NACA airfoil geometry parts

 

Mesh

In total, I meshed my geometry with 362,060 elements, with 95 % hexahedral cells. Additionally, I used a generic maximum and minimum face size of 6.10-2 m and 3.10 -4 m respectively. Furthermore, I created 2 face sizing sets for both the middle and inner parts. I chose an element size of 8.10-3 m for the middle part and 4.10-3m for the inner part.

Overall Geometry mesh
Overall Geometry mesh

Mesh around airfoil
Mesh around airfoil

I added an inflation layer at the boundary of the airfoil wall to capture the viscous layer accurately. I set 10 layers with smooth transitions as shown in the figure below:

10 inflation layers
10 inflation layers

 

Processing – ANSYS Fluent

I decided to carry out a transient simulation so I chose the transient option from the general menu and added the gravitational acceleration (-9.81 m/s2 in the Y direction). I also used the density based solver because I am dealing with a compressible flow at relatively high velocities.

I selected the K-Omega SST model which is suitable for this type of simulations (adverse pressure gradients, transonic flows, and airfoils).

I activated the Energy model and then I changed the fluid material from air with constant density to air as an ideal gas.

Fluent Setup 1
Solver Window

Fluent Setup 2
Viscous Model window

Fluent Setup 3
Material Window



During the meshing process, I created 2 boundaries, a Pressure Farfield boundary and a wall boundary that represents the airfoil itself.  I entered 0.45 for the Mach Number.

Boundaries
Boundaries

Far field conditions
Far field conditions

In the last part of running the simulation, I initialised using the hybrid initialisation method and finally, I chose a time step of 0.00005 S and adjusted (increasing /decreasing) accordingly.

cartier love bracelet replica, christian louboutin replica,christian louboutin replica, cartier love bracelet replica,cartier love bracelet replica, christian louboutin replica,van cleef and arpels replica, red bottoms replica,cartier love bracelet replica