Ahmed body is a car model

Description of the Ahmed body and its importance:

Ahmed body is a 3D model represents the general passenger car it shows how the car faces the fluid that\'s air effect surface of the real car. The high-pressure air not only shows the effect on surfaces it also shows effect on the steering while driving the car, balancing the car is nothing but to maintain lift and drag forces which are generated and it also reduces the speed of the car. Ahmed body it consists of the three parts one is the inlet at a velocity of 50m/s second is outlet pressure is zero gage pressure car model is surrounds the symmetry walls. In this case, fluid flows over the Ahmed body, therefore, generate the encloser at the given dimensions.

The above geometry shows the Ahmed body and this parts inlet, outlet and symmetry wall.

Importances:

1. Reduces the drag coefficient which is effects the Ahmed body.

2. To analyses the air effect on the surfaces of the car model.

3. Helps to increase the speed of the model.

4. To maintain the balancing of the steering due to drag and lift forces generated while driving the car.

Covering the enclosure:

In this case, the fluid flows over the model, therefore, create an enclosure is necessary.

Given parameters:

Inlet velocity is 50 m/s,

Temperature is 300c,

Outlet pressure is 0 gauge pressure,

.\'. Flow becomes the turbulence flows,

The density-based solver is used,

Inflation layer:

Performing a grid dependence test:

Improper mesh gride size effect flow of the fluids on the model, therefore, the grid dependence test is necessary. This test is nothing but increasing the mesh quality of the model.

In this case, three gride dependence tests are carried out:

1.Mesh size 0.06m

The fig. shows the finer mesh of the Ahmed body it\'s element size is 0.06m, the no. cells are the 86278. Good quality of the mesh increase the results.

Vector polt:

The above vector plot shows how the vector particles(ex.pressure, velocity) affect the surface of the Ahmed body. The inner enclosure is more effective as compared to the outer enclosure.

Residuals plot:

In this case, 500 iterations are carried out. It shows how the velocity, energy, turbulences are effected.

Velocity:

The above fig. shows how the velocity of the fluid is effected. The max velocity 1e+02 m/s & mini velocity is 0 m/s.

Pressure polt:

The above pressure polt shows the pressure effects on the body.

Max 1.517e+3

Mini -5.95e+3

The -ve pressure is generated due to the car is moving the with high velocity in this the outlet side vacuum is created.

2. Mesh size 0.02m

Residuals plot:

This polt shows the similar to the first case, in this case, we check residuals at mesh size o.03.

Velocity polt:

The figure shows how the velocity effect the Ahmed body.

Maxi 1e+2 m/s

Mini 0 e+ m/s

Pressure polt:

This polt shows the inlet part effect the maximum pressure and outlet part effect the minimum pressure.

maxi 1.517e+3

mini -5.953e+3

3. Mesh size 0.02 m

Residuals plot:

The residuals start at point 1e+00 after 50 iterations slow down after that gradually decreases.

Velocity polt:

The above plot shows the velocity effect the Ahmed body maximum velocity 1e+2 m/s, minimum velocity is 0 m/s.

Pressure polt :

Maximum pressure is 1.517e+3 Pa

Minimum pressure is -5.953e+3 Pa

Chart :

The above graph shows the magnitude of velocity at 2 and 3m away from the Amed body in a downstream direction.

The above figure shows how the Ahmed body effects the air pressure. The inlet portion faces more pressure and both the sides is less pressure. The backside faces less pressure since Vaccum is generated. When the car moves with a high-velocity in that case front end face more pressure in that case sides are in well-finished shapes in that case air passes away from the body. In that case, there is no air is present at the backside, in that case, a vacuum is created. Therefore the pressure is negative generated.

Interference command:

In this case, interference command is used to interface two enclosure parts.

Velocity animation:

The velocity animation shows how the Ahmed body effects the velocity of the air.

Conclusion:

!.The Ahmed body is nothing but a car model when the model moves with the high velocity in this the front side faces more pressure.

2. The sides of the Ahmed body is well finished in that case the air pressure is less effected as shown in the above results.

3. Therefore backside faces less pressure in that case negative pressure is generated.