Computational Study on the Effect of Aft-Body Attachments on Base Drag Using Locked Vortex Flow Management Technique

Abstract

An attempt to minimize drag has always been a key concern for the expectation of high performance. Bluff bodies are usually dominated by pressure drag which is a result of flow separation, and it accounts for a considerable amount of the total drag. Drag reduction techniques prove to be a major aid in minimizing vortex shedding and wake; this can be applied while building launch vehicles and missiles. Flow over bluff bodies exhibit vortex shedding and produce large wakes which can be countered with the help of passive flow control technique. The modification in the design of the body with the help of attachment of splitter plates for trapping the vortices proves to significantly reduce the base drag, and it is considered as one of the most effective passive control techniques. The paper focuses on the influence of after-body attachments on the base drag and the evaluation of the effectiveness of these attachments. Comparison of variation in base drag is made considering three cases—initial analysis is done on a body without any attachments; further observation of changes in base drag is done with the attachment of a shaft to the base of the body and then with the attachment of single splitter plate to the shaft. Examining the simulation results, it can be observed that with the attached splitter plate design, vortex shedding is suppressed along with the achievement of pressure recovery. The work is a computational study on the effect of aft-body attachments on base drag. Locked vortex method can be considered as an effective method in reducing base drag. Further studies are planned with the attachment of double or triple splitter plates with experimental assessments.