The different types of area in Fluid Mechanics are.

• Normal area
• Cross sectional area
• Plane area
• Resisting area
• Surface area
• Shear area
• Crushing area
• Tearing area
• Projected area
• Flow area.

Normal area: Normal area is measured without touching the body which is visible in 2D

Flow area (in a pipe): It depends on the fluid touching the sides of wall. The flow area is calculated as the total cross-sectional area of the pipe minus the cross-sectional area of the empty space above the water