Modern vehicles undergo extensive aerodynamic testing to ensure that they can minimize drag, thus achieving optimal fuel efficiency. However, a new wave of automobiles, including Tesla’s Cybertruck, has turned heads with its unorthodox shape. By designing two sports vehicles - one with a traditional rounded body and the other taking inspiration from the Cybertruck - the aerodynamic analysis revealed increased air pressures and velocity distributions resulting from the 'boxy' design.

Design Sketches

Before creating the 3D CAD models of the two vehicles intended for simulation, sketches were produced to inspire the designs. A variety of form factors, ranging from completely rounded panels to bodies with sharp edges, were drawn. Since the analysis aimed to compare the two extremes of body forms, the two most contrasting sketches were selected to proceed to the CAD stage.

Figure 1. Sketches

Renders

Both extremes of the sports car forms were rendered in Fusion360, with additional features such as the rear wing of the rounded vehicle design incorporated to facilitate comprehensive discussion points during the aerodynamic analysis stage. Renders depicting both vehicles were generated to vividly showcase their respective designs. While further enhancements, such as detailing the headlights, were conceivable, their incorporation would yield negligible impact on the analysis and thus were not integrated into the models.

Figure 2. Renders

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Thermo-Fluid Analysis

Three primary analyses were conducted on the vehicles: 2D velocity and pressure distribution, surface pressure analysis, and flow trajectories. Understanding 2D velocity and pressure distributions is pivotal in shaping vehicle surfaces to minimize drag and enhance stability, thereby improving fuel efficiency and overall performance. Surface pressure analysis ensures optimal balance and reduces lift, contributing to enhanced handling and safety. Additionally, flow trajectory analysis guides design modifications aimed at reducing turbulence, thus enhancing aerodynamic efficiency and fuel economy. These fundamental concepts are critical for the optimization of car aerodynamics, resulting in vehicles that are more efficient and refined.

Figure 3. Flow trajectories on the rounded body

Comparison of Vehicle Designs

Flow simulations revealed notable variations in pressure distribution between the rounded body design and the Cybertruck inspired design, particularly around the front bumper edge, where pressures were notably higher. A comparison between different configurations illustrates the contrast between a curved and sharp-edged front bumper. Moreover, examination of the rear of the car revealed a region of significantly reduced velocity. This phenomenon can be attributed to the presence of sharp edges, wherein airflow, traveling parallel to the car, fails to converge efficiently at the rear, unlike the smoother airflow patterns observed with curved designs. In such instances, the curved rear facilitates earlier convergence of airflow from the top and bottom of the car, enhancing aerodynamic efficiency.

Download the full report below to view visualisations of every piece of analysis carried out on the vehicles, and for detailed drag calculations.

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