This case study demonstrates the capabilities of shonDy and shonMesh in simulating complex automotive scenarios, specifically a car navigating through a channel with speed bumps and water-filled puddles. The simulation provides insights into the car’s suspension dynamics and fluid interaction.
Case description
In this case, the car travels through a channel with the dimensions illustrated in the figure below. Within the channel, there is a segment containing speed bumps. The gaps between the speed bumps are filled with water, forming puddles. The speed bump segment begins approximately 8 meters into the channel, and the total length of this segment is about 14 meters. The car travels at a speed of 20 km/h, navigating through puddles that are up to 8 cm deep.
Geometry
The channel’s geometry was generated based on the above sketch using shonMesh, while the car’s geometry is the DrivAer Model, developed at the Institute of Aerodynamics and Fluid Mechanics at the Technische Universität München . This model serves as a generic representation designed to bridge the gap between overly simplified models like the Ahmed body and intricate production cars.
The STL file is shown in the figure below, along with the 3D geometry of the channel, including the speed bumps.
The left image below provides a detailed view of the speed bumps. The exact geometry of each bump is as follows: The bumps are 3.9 meters wide and 12 cm high, with three speed bumps on each side of the channel. The right side starts half a bump earlier than the left.
The right image shows the speed bumps (transparent) along with the geometry of the fluid in the puddles. Each puddle contains approximately 100 liters of water.
Case Setup
In this simulation, the car begins moving after a delay of 1 second, accelerates from 0 to 5.5 m/s over a span of 2 seconds, and then maintains this velocity until the end of the simulation. The total simulation time is 10 seconds, representing the duration required to traverse the entire channel. The precise velocity profiles are illustrated in the diagram below.
Liquid Setup
The liquid region is divided into four equally sized puddles, with a total simulated liquid volume of 0.39 m3. Each puddle contains approximately the same volume of water. For this simulation, a fluid particle radius of 2.5 mm was used, resulting in a total of approximately 3.1 million particles. This high particle resolution ensures an accurate representation of fluid behavior as the car interacts with the puddles.
Results
The video below provides an overview of the simulation results. It highlights the deformation of the car’s suspension system as it traverses the speed bumps and ramps within the channel. Additionally, the video demonstrates the distribution and coverage rate of the fluid on the car, with particular focus on the area around the front-right tire.
Suspension System Reaction
The diagrams below illustrate the reaction of the car’s suspension system over time. The left image displays the deformation of the rear suspension system, while the right image focuses on the front suspension system. These insights help analyze how the car’s dynamics respond to the speed bumps and fluid interaction.
