Question

A s shown in Figure 1, the flow field s of cricket balls in a uniform flow were visualized by using oil smoke techniques (a) From the flow visualization results shown in Figure 1(a), one can see the flow over the lower surface of cricket ball separates earlier than the flow over upper surface. Please give the brief reasoning for this phenomenon and the physics behind this. Based on the knowledge you learn in aerodynamics, which direction (upward or downward) do you expect the cricket ball will move normal to its flight path? Give the brief reasoning for your answer. (10 %) (b) From the flow visualization results shown in Fig. 1(b1) & Fig. 1 (b2), one can see the flow over the surface of cricket ball of Fig. 1(b2) separates earlier than the flow of Fig. l(bl). Based on the knowledge you learn in aerodynamics, which drag is larger (Fig.1(bl) or Fig. 1(b2))? Give the brief reasoning for your answer. (1000) 縫合線个 speed ↑F1レ seam Fig. 1(bl) Fig. 1(b2) Figure 1(a)

Answer 1

to ball om ce/

pueare and