Challenge

Week 3 - External flow simulation over an Ahmed body.

MMohammed Dhukka15 Oct 2021

AIM

To simulate flow over the ahmed body , ahmed body is stream line type , to get the result of velocity , pressure , lift and drag . To get result around it . To consider the different size of mashing, study of stagnation point, velocity& pressure profile around the body.

INTRO / DETAILS AND IMPORTANCE IN PRACTICAL

To provide proper enclosure around the body , given the proper inlet outlet names , given velocity as per given in challenge , consider and check the interference check for both the enclosure

It is used in calculating the lift,drag force, and coefficients of car body , airplane , rockets and missiles and other aerial vehicles,

It widely used in aerospace and automobile industry.

Velocity and pressure couture’s are vital parameters used to consider in aerospace and automobile industry.

Study of parametric study is used to consider for mashing and comparisons of other parameters , due to which we get the value for requirements and if any modification is needed for body.

SOLVING AND MODELING DETAILS / SOLVING DETAILS

Consider the proper enclosures, both small and large enclosures with un symmetry dimensions, dimensions are as per given in videos. In meshing page , consider details mashes , with sizing , different elements and sizes ,given names for inlet and outlets , body and symmetry walls .

In Setup given proper velocity and pressure, material property is considered, consider density based solver instead of pressure based , because velocity is 25 m/s.

In post processors consider plane and calculated all values of pressure and velocity. velocity couture.

Consider the plane cut at z section and calculated the all values pressure, velocity and vector plot.

Vector plot shows all the flow around the Ahmed body .

Velocity and pressure couture photos is attached along .

Vector plot showing wake region photos is attached

Ahmed body is similar like car body and small in streamline , such shape is used to calculate all the value of car body.
By providing proper enclosure we can calculate and analysis pressure on all side of body, positive ans negative pressure, pressure gradient, pressure drop , etc.
Can calculated the velocity at all parts of car and other body
Can calculate the stagnation point on cars and airplane /rocket /missiles etc,
Can consider the lift /coefficient of lift and drag /coefficient of drag on all moving body , of car , bike , especially in air plane , missiles and rockets , wing and air foil analysis .
Analysis and study of different type of air foil , to find out how much lift and drag produce by airfoil.

Description of wake reason

As flow pass through the Ahmed body the flow is attached to the surface of the body , as flow is attached to the body , at the end of body there is flow is increased rapidly due to cut section of body , as velocity increase rapidly and pressure decrease drastically so there is negatively pressure is seen in wake region , as flow separation is occurs .

Stagnation point

Stagnation point is the point where flow velocity is zero and pressure is maximum, due to decrease in velocity the pressure is increase rapidly. it is seen mostly at the nose of the any body

PLOTS AND CONTURES ARE ATTACHED

PRESSURE CONTURE ATTACHED PRESSURE PLOT CURVE