Define frontal area of a body subjected to external flow. When is it appropriate to use the frontal area in drag and lift calculations?

Short Answer

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The frontal area of a body subjected to external flow is the area of the body that faces the flow, being perpendicular to the flow direction. It is the "shadow" of the body as seen in a plane projecting the geometric outline of the object in the direction of the flow. It is appropriate to use the frontal area in drag and lift calculations when considering the shape of the body, the effects of fluid viscosity, streamlined bodies in motion, and incompressible flow situations. The frontal area helps in better understanding the interaction of the body with the fluid medium and calculating forces correctly.

Step by step solution

01

Definition of Frontal Area

The frontal area of a body subjected to external flow is the area of the body that faces the flow, i.e., the area that is perpendicular to the direction of the flow. It is the "shadow" of the body as seen in a plane projecting the geometric outline of the object in the direction of the flow. The frontal area is important in determining the drag and lift forces experienced by the body when subjected to a fluid flow.
02

Appropriate Use of Frontal Area in Drag and Lift Calculations

Frontal area plays a significant role in calculating drag and lift forces acting on a body in fluid flow. The drag force is the force that acts opposite to the direction of the flow, while lift force acts perpendicular to the direction of the flow. It is appropriate to use the frontal area in drag and lift calculations when: 1. The shape of the body in the flow affects the flow separation and consideration of the whole body geometry becomes necessary. 2. The effect of fluid viscosity on forces should be taken into account. 3. We are considering the forces acting on streamlined bodies moving through a fluid. 4. The flow is incompressible because high pressure occurs only on the front part of the body. In these cases, it is essential to use the frontal area to determine the overall force acting on the body due to the fluid flow (drag or lift). The frontal area helps in better understanding the interaction of the body with the fluid medium and calculating forces correctly. In summary, the frontal area is the area of a body facing the fluid flow direction, and it is appropriate to use it in drag and lift calculations when we need to consider the shape of the body, the effects of fluid viscosity, the consideration of streamlined bodies in motion, and when dealing with incompressible flow situations.

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