@techreport{oai:jaxa.repo.nii.ac.jp:00002404, author = {原田, 正志 and Harada, Masashi}, month = {Mar}, note = {A method for optimizing a propeller or windmill in a wind gradient has been developed, based on the lifting-line theory. This method takes the effect of trailing vortices and shed vortices into consideration, and consists of two fundamental major concepts. The first is the description of the problem by quadratic functions. The second concept is the reduction of the number of unknown variables using the periodical characteristics of the solution. In the first concept, optimum propeller design is converted into an optimization problem solved by a simple procedure. Using the latter concept, the number of design operations is reduced to a number executed within practical computation time. The validity and accuracy of the solution obtained by this method are carefully evaluated and proven using Prandtl's propeller theory. The solution shows that the propulsive efficiency of the optimum propeller with a wind gradient is larger than that without a wind gradient. The solution also shows that the optimum propeller in a wind gradient generates thrust even without an internal power supply. The windmill for a windmill ship is also designed, and the advantage of a windmill in a wind gradient shown., ISSNの誤記: 1349-1148, Incorrect ISSN: 1349-1148, 資料番号: AA0047408000, レポート番号: JAXA-RR-03-016E}, title = {Optimum propeller or windmill design in a wind gradient}, year = {2004} }