November 4, 2020
Facing convergence problems and low accuracy of simulation results due to the low number of mesh cells in their computer, ARUS Andalucía's Aerodynamics department came to Nimbix. The team needed a significant increase in the number of available mesh elements to see greater accuracy in their vehicle simulation results.
ARUS Andalucía's racing team's focus was on the electric and combustion aspects of their vehicles.
First, varying the heights on the axles, several simulations were performed to see the vehicle's behavior in a straight line with different pitch and yaw angles. Afterward, they took a constant reference height and varied the velocities of the incidence of the flow on the vehicle. They obtained the lift coefficient CL and downforce, drag coefficient CD and drag force, the center of pressures, forces on the axles (longitudinal and lateral aerobalance), and air flow rate to the cooling system in both studies.
Later, having modeled two ways to obtain the desired CFD results, they studied the vehicles in curves. Once the modeling was complete, the Aerodynamics team carried out the study, including varying the pitch, roll, and yaw angles and obtaining the vehicle's behavior in a way closer to reality than it had been before. The team again obtained the CL, CD, pressure center, and all the information previously mentioned for the straight line.
Both simulations, one with a straight line and one a curve, allowed the team to create several aerodynamic maps that illustrated how the single-seaters are affected in various situations.
Most variations, including pitch, yaw and roll angles, velocity, and cornering condition, are non-negligible in the aerodynamics results. Due to this, the car's dynamic behavior will change, and it's essential to carefully design the aerodynamic package to benefit the dynamic behavior and reduce the lap time.
ARUS Andalucía's Aerodynamics department says their project was made possible this year by using STAR-CCM+ on the Nimbix Cloud. The combination allowed them to perform more simulations in less time, increasing the number of cells and, consequently, the accuracy of the results.
"The old computer," Samuel Torres, CFD and dynamics at ARUS Aerodynamics department, explains, "belongs to the University of Seville and is not always available for us. There are queues to use the computer, allowing the team only a short amount of time to run advanced simulations, resulting in the Aerodynamic department only executing the most basic simulations".
Continuing, Torres says, "it used to take about 24 hours to prepare and run a simulation of 10 million cells on our old computer. Using the Nimbix Cloud, we run up to 6 analyses of 30 million cells in parallel, having results in less than 8 hours."
"Thanks to Nimbix," Torres says, "our Aerodynamics department has been able to greatly decrease the number of times simulations had to run. They are allowing us to extend the team's annual CFD goals and make our dream that ARUS is one of the best Formula Student teams a little closer".
"Nimbix has a very intuitive and comfortable platform to use," says Torres, "anyone can access and work with the software they want and when they want, in addition to the cloud storage, which you can access from any computer, anywhere and at any time."