# CFD Costs

Christian Kongsgaard
2021-04-13

In this section we give an overview of expected costs of running a Virtual Wind Tunnel simulation. The scenario we show here, includes cost and time for the meshing task and Virtual Wind Tunnel task, with the specified number of angles, shown in the table below. The time and cost in the tables are approximate and can not be relied upon as absolute.

## Change in Number of Cells

In this table we change the number cells in the CFD mesh. By increasing the resolution in the mesh the number of cells grow. That both affects the meshing time, but also the time it takes to simulate each angle.

Number of Cells
1.0 million
5.0 million
7.5 million
10 million

Resolution at Point of Interest
0.5 m
0.5 m
0.25 m
0.25 m
Concurrent CPUs
384
384
384
384
Turnaround Time
15 min
65 min
100 min
130 min
Iterations
500
500
500
500
Cost
40 €
195 €
290 €
400 €

## Change in Number of Angles

In this table we change the number of angles that we run in the Virtual Wind Tunnel. While the overall turnaround time stays the same, the cost increases as you add more angles to the simulation. The turnaround stays the same, because all the angles are run concurrently, and we can therefore get all the angles, no matter how many back in the time it takes to simulate one.

Number of Angles
4
8
12
16

Number of Cells
1.0 million
1.0 million
1.0 million
1.0 million
Resolution at Point of Interest
0.5 m
0.5 m
0.5 m
0.5 m
CPUs per Angle
24
24
24
24
Concurrent CPUs
96
192
288
384
Turnaround Time
15 min
15 min
15 min
15 min
Iterations
500
500
500
500
Cost
10 €
20 €
30 €
40 €

## Change in Number of Iterations

In this table we change the number of iterations that we run the simulations for. When everything else stays the same, then increasing the number of iterations proportional increases the time and cost.

Iterations
500
1000
1500
2000

Number of Cells
1.0 million
1.0 million
1.0 million
1.0 million
CPUs per Angle
24
24
24
24
Concurrent CPUs
384
384
384
384
Turnaround Time
15 min
30 min
45 min
60 min
Cost
40 €
75 €
115 €
155 €

## Change in Number of CPUs per Angle

In this table we change the number of CPUs that we use per angle. That increases the number of CPUs that we run concurrently, but at the same time the simulation time decreases, which means that the overall cost stays the same.

CPUs per Angle
4
8
18
24

Number of Cells
1.0 million
1.0 million
1.0 million
1.0 million
Concurrent CPUs
64
128
288
384
Turnaround Time
80 min
40 min
20 min
15 min
Iterations
500
500
500
500
Cost
40 €
40 €
40 €
40 €