5SHY4045L0001 Design simulation | Cradle CFD to help Donghai University solar car fleet technology breakthrough

The Tokai University Solar Car Team took 5th place in the Bridgestone World Solar Challenge 2023 (BWSC2023), one of the world's largest solar car races, held from October 22 to 29. The team used Cradle CFD, Hexagon Industrial Software's thermal fluid analysis software, for digital simulation to develop the body with excellent aerodynamic performance.

The Tokai University Solar Car team competed in the Challenger group, driving 3,000 kilometers through the harsh Australian desert at a cruising speed of more than 90 km/h, using only a small amount of energy generated by sunlight during the ride.

Since 1993, the team has participated in the BWSC competition held every two years in recent years, winning the title twice in a row in 2009 and 2011. In 2019, they finished second, and then started designing a new body for the BWSC2021, but it was cancelled. Since then, they have been hard at work developing the new body, the BWSC2023, which is their first challenge in four years.
As a countermeasure to the positioning plate placed at the rear end, the 2023 model is equipped with a small pneumatic device (patent pending) called the "Turbulent vortex suppression blade (TVS blade)", which is used to suppress the rear vortex (vorticity). The following analysis results show that the backward vortex can be successfully suppressed. The device (1) reduced the air resistance by about 1.8%, and the further improved device (2) succeeded in reducing the air resistance of the entire solar car by 4.5%.

In the high-precision analysis of a total of about 700 million units, a detailed grid was generated for the final performance evaluation, and the results showed that the aerodynamic performance of the 2023 model exceeded that of the 2019 model, overcoming the severe impact of rule changes on aerodynamic performance. The analysis takes less than a week on a cluster computer owned by Foton LABS. In the early stages of development, they performed the analysis with a slightly thicker grid, about one day per case, and simulated more than 100 body shapes.

Professor Kota Fukuda, from the Department of Aeronautics and Astronautics at Tokai University's School of Engineering and director of Tokai University's Solar Vehicle team, said:

"Cradle CFD is very helpful for efficiently analyzing flows around complex geometry, and it is able to quickly generate meshes, even for complex geometry. In solar vehicle development, we need to study many complex shapes in a short period of time, and Cradle CFD can be used effectively for this purpose. From an educational point of view, the friendly Japanese interface is easy to understand for students new to CFD (Computational Fluid Dynamics) /CAE (computer-aided Engineering), and the features are easy to learn. With this user-friendly software, I can see that my students are charting the ideal learning curve. The immediate response from the support team was also very helpful.

Since engineers now and in the future must make full use of CAE, I think it would be very effective for the university to have students actually use CFD and other CAE software to analyze and make actual products based on their analysis results through the development of solar cars. I am sure that many of the students who study here will be active in the industrial sector in the future in various fields, including the development of ecological transportation. We hope not only to use CFD for future solar vehicle development, but also to use various CAE technologies for future solar vehicle development.