Getting Aerodynamics Right - Mechanical Simulation Corporation partners with AirShaper
Introduction
CarSim by Mechanical Simulation streamlines the design, engineering & testing of passenger vehicles
and light-duty trucks based on physical inputs, like vehicle dimensions and detailed properties of eachvehicle subsystem. The more detailed this input, the more accurate the CarSim output. Since many
vehicle properties are already known to a high degree of accuracy, it makes sense to do the same foraerodynamics as early in the simulation process as possible.
To get the aerodynamic properties right, CarSim announces its partnership with AirShaper, the cloud
platform for aerodynamic simulations (www.airshaper.com). The fully automated workflow allows users
without a background in aerodynamic simulations to upload a 3D model, set up, and run simulations.
The resulting aerodynamic data can be fed directly into CarSim.
Customer benefit- OEM: Vehicle manufacturers constantly look for ways to shorten design cycles to go to market faster.
Detailed aerodynamic coefficients allow for accurate predictions on power consumption, side windsensitivity, etc. It brings the CarSim simulations a step closer to the real performance of the vehicle,
reducing time and resources required for the physical testing that follows.
- Suppliers: bringing profitable yet safe vehicle components and sub-systems to market requires
accurate knowledge of the loads acting on components and the dynamics of the vehicle. With
aerodynamics influencing a car’s balance & performance, both on straight lines and in corners, moreaccurate aerodynamic coefficients can make a measurable difference.
How it works (see details in Appendix)
Step 1. Upload the 3D model of your vehicle to AirShaper. This can be a rough concept model (AirShaper
accepts open surface models with holes) or a detailed (preproduction model.
Step 2. Set the driving speed, matching the average speed of your vehicle. Select the angles of attack,according to the number of angles you want to specify in CarSim. By default, these are [0°, 20°, 90°,135°, 160°, 180°] or more for racecars.
Step 3. By default, the AirShaper outputs the aerodynamic forces & moments in a format that can beeasily imported into CarSim.
Pricing
The AirShaper platform does not require any purchase of software or monthly fees. Nor does it require
expensive hardware or software. You simply pay per simulation (see www.airshaper.com/pricing).
The standard simulation package to obtain aerodynamic values for CarSim starts at 5.250€ ex VAT. This
includes 6 Ultimate Simulations. On request, higher accuracy and/or numbers of simulations areavailable depending on your needs. Request a quote.
For CarSim and TruckSim pricing and information, please contact Mechanical Simulation athttps://www.carsim.com/contactus/index.php

Appendix: how to integrate AirShaper results into CarSim
This appendix describes how to use AirShaper to integrate accurate estimations for aerodynamic
coefficients into CarSim. The example that is used is the generic B-class car that is included in every
version of CarSim.
Step 1 – Defining the required side slip angles beta--Regular cars: for regular cars, like the B-class example model, there are 6 side slip angles thatare used for the aerodynamic simulations: 0°, 20°, 90°, 135°, 160° and 180°. Of course, you arefree to increase the number of points on the curves, should you require more accuracy.
Race cars: for race cars, typically more accuracy is required in terms of side slip angles, but also
in terms of ride height and so on. With AirShaper, you can calculate the aerodynamic
coefficients for each setup of your car (ride height front/back), on top of the different side slipangles.

Step 2 – Running the simulations on AirShaper-Create a free AirShaper
Start a new project at Detailed or Ultimate Accuracy (depending on your needs).
Upload a 3D stl file of your car
On the setup page, choose “moving”, provide the average driving velocity and rotate the model
to match the wind orientation & side slip angle. Select the right units and click next.

-On the payment page, fill in your company & credit card details and launch the simulation
Repeat this process for each side slip angle. You can launch them all in parallel.

Step 3 – Extracting the aerodynamic parameters
Once the simulations are finished, you’ll get a full report for each side slip angle beta. In those reports,
you can find the aerodynamic forces & moments that are relevant for CarSim:

Via the frontal surface area of the car, these coefficients will be translated by AirShaper into thecoefficients needed for CarSim: CFx, CFy, CFz (for the forces), CMx, CMY, CMz (for the moments).
Step 4 – integrating the aerodynamic
To integrate these parameters into your CarSim project, you can go to the aerodynamics section of thecar and either input the parameters directly, or use the PARSFILE to provide them:Once you have done this for each of the aerodynamic parameters (CFx, CFy, CFz for the forces, CMx,CMY, CMz for the moments), the aerodynamics of your CarSim simulation have been set up.