Simulation Example — Flow Over a 2D Sedan Car Shape

Overview

Automobiles on the roads today have various shapes and sizes, like sedans, hatchbacks, pick-up trucks, SUVs, sports cars and more. Each car model is optimized for a specific operation; for example, a sports car is designed to optimize the lift and drag forces acting on the car so that it can reach top speeds over a short duration and enhance maneuvering capabilities at high speeds. On the other hand, trucks are designed to be bulkier to carry heavy loads. Based on the car shape and size, they experience different drag forces. Automobile engineers focus on reducing the drag on a vehicle to optimize the vehicle’s performance and reduce fuel consumption or, in electric vehicles, extend battery life. Hence, it is important to study the flow field around a vehicle to analyze the impact of the forces acting on it, which is even more important when the vehicle is traveling at high speeds as the drag force is proportional to the square of vehicle’s velocity.

In this simulation, we will analyze the flow over a 2D sedan traveling at 20 m/s (or 72 km/hr) and compute pressure and viscous drag forces experienced by the vehicle.

Objectives

In this simulation, you will learn how to set up a simulation to analyze the flow over a 2D sedan cross section and to calculate various forces acting on the car.

Setup

Download the Mesh file required for setting up the simulation and associated Case & Data files here. Follow the instructions below to set up this simulation in Ansys Fluent starting with the Mesh file. In case you face any issues setting up or running the simulation, refer to the corresponding initial and final Case and Data files.

Alternate video link.

Results and Discussion

Let’s now analyze the simulation results and understand the physics of air flow over a 2D sedan car shape.