# Floating Point exception Error during Air Flow simulation

**URL:** <https://www.simscale.com/forum/t/floating-point-exception-error-during-air-flow-simulation/91922>\
**Category:** Project Support\
**Created:** [March 10, 2021, 11:27am UTC](https://www.simscale.com/forum/t/floating-point-exception-error-during-air-flow-simulation/91922 "2021-03-10T11:27:57Z")\
**Posts on this page:** 6\
**Page:** 1

<div class="post-metadata">

**Author:** ![iarora](https://www.simscale.com/forum/letter_avatar/iarora/32/6_22734026db12803ebb3e059622ac3534.png) [@iarora](https://www.simscale.com/forum/u/iarora)\
**Post date:** [March 10, 2021, 11:27am UTC](https://www.simscale.com/forum/t/floating-point-exception-error-during-air-flow-simulation/91922/1 "2021-03-10T11:27:57Z")

</div>

Hi!  
I’m trying to do a CFD analysis for air flow in a part of the city but I keep getting “floating point exception” in my simulation runs. I’m using the software for the first time so I’m not really sure how to fix it. I have seen the post that is linked with error but can’t. figure anything out.  
Any help would be great

> **[SimScale Login](https://www.simscale.com/workbench/?pid=1567154620002723150&mi=run%3A31%2Csimulation%3A20&mt=SIMULATION_RUN)**
>
> Log in to your SimScale account. SimScale makes high-fidelity engineering simulation technically and economically accessible. At any scale. In the cloud.

---

<div class="post-metadata">

**Author:** ![tsite](https://www.simscale.com/forum/user_avatar/www.simscale.com/tsite/32/47909_2.png) [@tsite](https://www.simscale.com/forum/u/tsite)\
**Post date:** [March 10, 2021, 11:31am UTC](https://www.simscale.com/forum/t/floating-point-exception-error-during-air-flow-simulation/91922/2 "2021-03-10T11:31:12Z")

</div>

Hi this is Fillia 🙂  
This issue has already been discussed in some posts. I would recommend having a look at the following post : **[Floating Point Exception Error](https://www.simscale.com/forum/t/most-popular-errors-of-simulation/92/3)**  
Best regards,  
Fillia

---

<div class="post-metadata">

**Author:** ![iarora](https://www.simscale.com/forum/letter_avatar/iarora/32/6_22734026db12803ebb3e059622ac3534.png) [@iarora](https://www.simscale.com/forum/u/iarora)\
**Post date:** [March 10, 2021, 11:40am UTC](https://www.simscale.com/forum/t/floating-point-exception-error-during-air-flow-simulation/91922/3 "2021-03-10T11:40:38Z")

</div>

Hi!  
I have checked that post but my numerics are non-zero so I’m not exactly sure what to do.

---

<div class="post-metadata">

**Author:** ![tsite](https://www.simscale.com/forum/user_avatar/www.simscale.com/tsite/32/47909_2.png) [@tsite](https://www.simscale.com/forum/u/tsite)\
**Post date:** [March 10, 2021, 12:36pm UTC](https://www.simscale.com/forum/t/floating-point-exception-error-during-air-flow-simulation/91922/4 "2021-03-10T12:36:06Z")

</div>

Can you explain to me what you mean by the Numerics being non-zero? Maybe you mean the boundary conditions? The Numerics are the settings of the solver [CFD Numerics | Simulation Setup | SimScale Documentation](https://www.simscale.com/docs/simulation-setup/numerics/)

---

<div class="post-metadata">

**Author:** ![iarora](https://www.simscale.com/forum/letter_avatar/iarora/32/6_22734026db12803ebb3e059622ac3534.png) [@iarora](https://www.simscale.com/forum/u/iarora)\
**Post date:** [March 10, 2021, 12:41pm UTC](https://www.simscale.com/forum/t/floating-point-exception-error-during-air-flow-simulation/91922/5 "2021-03-10T12:41:04Z")

</div>

Oh yes I mean the initial conditions and boundary conditions!

---

<div class="post-metadata">

**Author:** ![tsite](https://www.simscale.com/forum/user_avatar/www.simscale.com/tsite/32/47909_2.png) [@tsite](https://www.simscale.com/forum/u/tsite)\
**Post date:** [March 10, 2021, 1:56pm UTC](https://www.simscale.com/forum/t/floating-point-exception-error-during-air-flow-simulation/91922/6 "2021-03-10T13:56:34Z")

</div>

I see, you are right, but there are more suggestions in the post that you should test too:

1. Use upwind convection scheme

2. Double-check the initial and boundary conditions

3. Limit the time step

4. Apply under-relaxation

5. Try other linear equation system solvers

However, my personal suggestion is that you set the domain sizing according to Figure 5 here first: [Aerodynamic Flow Behavior Around a Vehicle Tutorial | SimScale](https://www.simscale.com/docs/tutorials/aerodynamic-simulation-vehicle/) Of course you do not have symmetry, so you will need to extend the domain to both sides. Make sure to increase the height too.

 ![height](https://www.simscale.com/forum/uploads/default/original/3X/c/3/c366204fb84722e9cf7824a211b7492c80d5e59d.png)

Best regards,  
Fillia