1938 Aerodynamics Characteristics and Flow Pattern for the Dimple Structure on a Sphere with Rotating
Details
It is known that the flow characteristics of the three dimensional bluff body such as a sphere depends on the surface structure. The purpose of this study is to clarify the relation of Aerodynamics characteristics and flow pattern for the surface structural change. In this study, the diameter of the test spheres are 42.6 and 100 mm. The number of dimples are 0, 104, 184, 328 and 504. Reynolds number is 1.27×10^5. Spin ratio α(α=V/U, V is rotational speed of the test sphere, U is uniform velocity) is changed from 0.049 to 0.198. The drag and lift are measured using a three components loadcell. The pressure around the test sphere is measured using a pressure transducer. And more, the flow visualization around the test sphere is performed applying the spark tracing method. As the results of these experiments, the drag and lift coefficient for the number of dimple, pressure coefficient, separation point and the flow pattern around the test sphere became clear.
