been advanced for the alleviation of this phenomenon, no fundamental solu- 

 tion to the problem is yet feasible because the details of the complex flow 

 are not known, and the analytical tools have not yet been developed to pro- 

 vide design guidlines. As a result, a majority of the work in this area is 

 fragmented and empirical in nature, being guided primarily by intuition and 

 observation; the results cannot usually be generalized and are restricted 

 to the specific application or investigation. 



The present study attempts to identify, through an extensive literature 

 survey, the work pertinent to the tip vortex rollup phenomenon and its 

 alleviation. Over 150 documents are identified and cataloged. In addition, 

 those alleviation concepts which hold promise for the delay of tip vortex 

 cavitation on marine propellers are given closer consideration, and appro- 

 priate experimental investigations are recommended. 



BRIEF DESCRIPTION OF TIP VORTEX LITERATURE 

 The large volume of literature devoted to the tip vortex rollup phe- 

 nomenon attests to both the importance of the associated problems and the 

 lack of a fundamental understanding of the mechanism involved. Approxi- 

 mately 60 percent of the papers reviewed in the present survey represent 

 experimental work which attempts to define the nature of the rollup process. 

 Although the results of these investigations have begun to identify the 

 pertinent parameters governing the vortex rollup process, they have not 

 provided the generalized tools necessary for its prediction. As a result, 

 the remaining 40 percent of the papers reviewed comprise experimental 

 studies which are directed solely to the solution of the tip vortex problem. 

 The literature dealing with the analytical representation of the viscous 

 rollup will be reviewed in the next section. 



A bibliography of all the literature reviewed is given in the Appendix. 

 In addition, a capsuled highlight of each of the bibliography references is 

 given in Table Al of the Appendix. As seen in the Appendix, the large 

 volume of tip-vortex-related literature offers very little information with 

 regard to marine propellers, and particularly to tip vortex cavitation. 

 Of the 40 percent of the literature dealing with tip vortex alleviation 



