International Science and Technology Journal

Rotating cylinders are distinguished from other bodies with the amount of their generated lift force at certain flow conditions. While its Lift force coefficient is highly affected by speed ratio that has been directly proportional to rotating speed of a cylinder. Its expected that free end status will reduce the design rotation rate to an actual rotation rate as a result of the deviation of the axial rotational into a spinning motion. This study is concerned with verifying the deviation of a free-end cylinder rotation about its symmetrical axis, and the detection of the consequences of that deviation and also its impact on the performance. A set of experimental tests was implemented on a cylindrical model at two different statuses, one of which is the free-end status while the supported-ends embodies the other status. The observed results clearly showed that there is a deviation in the axial rotational motion at free-end case, where the degree of deviation was strongly growing with the increase of operating power which uses to rotate the cylindrical model. Obtained results demonstrated to that the deviation had caused a obvious divergence between two statuses in terms of actual rotating rate of tested model, where the actual rotational speed of free end status decreased by up to 5 times at maximum operating rate compared to the other status. Furthermore, the mentioned diverge indicates to a depletion in consumed power which negatively affects the cylinder performance and then reduces the generated lift force through a decrease in speed ratio due to decrease in actual rotational speed of the cylinder.