Correct option is A
A circular disc of plate held normal to flow it will give maximum drag force bemuse here the streamlines will end abruptly which is not the case in others.
In turbulent flow, the drag force experienced by an object depends on its shape and orientation relative to the flow direction. When comparing different shapes with the same cross-sectional area, the total drag varies significantly due to differences in pressure drag and friction drag.
Drag Forces on Different Shapes:
Circular Disc or Plate Held Normal to Flow:
When a flat plate or disc is held perpendicular (normal) to the flow, it experiences a high pressure drag because the flow cannot easily move around the object. The flow separation occurs immediately at the edges of the plate, creating a large wake region and resulting in high drag.
Drag Coefficient: The drag coefficient for a flat plate normal to flow is significantly higher than that of other shapes.
Sphere:
A sphere has a more streamlined shape compared to a flat plate, but it still experiences significant drag due to flow separation and wake formation behind the sphere.
Drag Coefficient: The drag coefficient of a sphere is lower than that of a flat plate but higher than that of a streamlined body.
Cylinder:
A cylinder experiences drag due to flow separation, similar to a sphere, but the drag coefficient is generally higher than that of a sphere, especially when the cylinder is aligned with its axis perpendicular to the flow.
Drag Coefficient: It is higher than that of a sphere but lower than that of a flat plate held normal to flow.
Streamlined Body:
A streamlined body is designed to minimize drag by reducing flow separation and wake formation. The flow remains attached to the surface for a longer distance, resulting in a much lower drag force.
Drag Coefficient: The drag coefficient of a streamlined body is the lowest among the options provided.
