Development of a Prediction Method for Aerodynamic Noise Generated Inside Backdoor Groove Sections

Yuta Ito (Toyota Motor)･Satoru Yamada (Dassault Systemes)･Shirou Yasuoka (Toyota Motor)

Quietness is an important aspect of a vehicle's commercial appeal, and noise reduction has become one of the major development objectives. In recent years, with the spread of electrified vehicles such as HEVs and BEVs, the contribution of engine noise has diminished or even become negligible. Furthermore, advances in vibration and noise reduction technologies have lowered road noise and motor noise, resulting in the relative increase in the contribution of aerodynamic noise during high-speed driving. Aerodynamic noise is caused by pressure fluctuations around the vehicle's shape and groove sections. The ability to evaluate these factors at the early stages of design is extremely important for automobile manufacturers, and prediction methods for aerodynamic noise generated by vehicle shapes have been developed thus far. In this presentation, we report on the development of a prediction method for aerodynamic noise generated inside the backdoor groove section, using numerical fluid analysis based on the Lattice Boltzmann Method (LBM), along with correlation results between simulations and actual measurements.

Prediction of Aerodynamic Noise from Cooling Fans in Automotive ECUs using Acoustic Analogy

Yuichiro Konishi･Shinichi Mitsubori･Naoto Tada･Yosuke Soeda･Masanori Yokota (Panasonic Automotive Systems)

In the development of in-vehicle infotainment Electronic Control Units (ECUs), air-cooling solutions are required to address thermal and acoustic challenges due to increasing vehicle intelligence and electrification. To improve noise control strategies, this study introduces Computational Fluid Dynamics (CFD) combined with an acoustic analogy approach to predict aerodynamic noise generated by ECU cooling fans. The effectiveness of the proposed method is verified by comparing simulation results with experimental noise measurements for different fan usage cases.

Application of Aerodynamic Surrogate Models in Actual Development

Kohei Seo･Keigo Shimizu･Yusuke Nakamura･Takenori Hiraoka･Akihiro Nakata (Mazda)･Takuji Nakashima (Hiroshima University)

We have developed an aerodynamic surrogate model capable of rapidly outputting 3D flow fields for vehicle shapes to achieve a significant reduction in the aerodynamic evaluation period. Furthermore, we have combined it with an evaluation method that utilizes Local drag, which divides the flow field into three components to facilitate the practical application in actual development processes.

Study of Boundary Conditions in CFD Analysis of Brake Disc

Shigenori Fujisawa (Advics)

The cooling performance of brake disc is influenced by the vehicle in which they are installed and by surrounding components. When predicting actual performance using CFD analysis, it is necessary to consider the boundary conditions that reflect installation on a real vehicle. However, these boundary conditions are not well known. Therefore, we studied the boundary conditions by measuring on the vehicle and performing CFD analysis using a vehicle model.