Chapter 9 - Drag and Lift

Abstract

In Chapters 7 and 8Chapter 7Chapter 8, we gained a lot of knowledge about “internal flow.” This chapter deals with the drag and lift forces a fluid exerts on a submerged body. Examples of these types of systems are automobiles, airplanes, golf balls, ships, bridges, and buildings. The importance of this subject matter is proved by streamlining the body shape of an automobile to reduce the drag, by increasing the fuel consumption rate and by drastic improvement in mileage. Similarly, an airplane cannot fly without an adequate lift force. The flight distance of the golf ball is two to three times the flight distance of the smooth ball. That is, the dimple of the golf ball controls the boundary layer of the flow on the ball surface and reduces the drag. Here, we discuss the drag coefficient of the object in the fluid, the lift coefficient, and the concept of the boundary layer.