AHEMD BODY COMPARING TWO MESHING METHODSNabeel Fathi

AUTOMOTIVE AERODYNAMIC PROBLEM

Problem Description

• The Ahmed body is widely used in the automotive aerodynamic literature, to simulate the airflow over a simplified, ground vehicle geometry.

• In this research two types of meshes were tested to simulate the external flow over Ahemd body.

• Ansys work bench was used, and results are compared.

• Mesh 1• Face Sizing• Inflation 10 layers

Ahemd Body

Inflation layers

• Mesh 2• An additional 3d body was modeled to enfold the Ahemd body.• The 3d body mesh was body sized, meshing the fluid around the Ahmed body.• Same element size was used for both cases.

Ahemd Body

3D enfolding body

• Mesh 1 • Mesh 2

Velocity Contour

• Mesh 1 • Mesh 2

Velocity Vector Rear

The velocity profile of the fluid behind the Ahmed body.

Mesh 1 Mesh 2

Velocity Profile 0.08 m behind the body

Velocity Profile 0.18 m behind the body

Computational Effort.

• The number of elements was much higher for mesh 2.

• The computational time was high for mesh 2.

• The two results were relatively close.

The End