국내 최대 기계 및 로봇 연구정보

기술보고서

기술보고서 게시판 내용
타이틀	AND PRIORITIES
저자	A REASSESSMENT OF HEAVY-DUTY TRUCK AERODYNAMIC DESIGN FEATURES AND PRIORITIES
Keyword
URL	http://www.dfrc.nasa.gov/DTRS/1999/PDF/H-2283.pdf
보고서번호	NASA-TP-1999-206574
발행년도	1999
출처	NASA Dryden Flight Research Center
ABSTRACT	Between 1973 and 1982, the NASA Dryden Flight Research Center conducted 밹oast-down?tests demonstrating means for reducing the drag of trucks, buses, and motor homes. Numerous configurations were evaluated using a box-shaped test van, a two-axle truck, and a tractor-semitrailer combination. Results from three configurations of the test van are of interest now in view of a trucking industry goal of a 0.25 drag coefficient for tractor-semitrailer combinations. Two test van configurations with blunt-base geometry, similar to present day trucks (one configuration has square front corners and the other has rounded front corners), quantify the base drag increase associated with reduced forebody drag. Hoerner뭩 equations predict this trend; however, test van results, reinforced by large-scale air vehicle data, indicate that Hoerner뭩 formula greatly underestimates this dependence of base drag on forebody efficiency. The demonstrated increase in base drag associated with forebody refinement indicates that the goal of a 0.25 drag coefficient will not be achieved without also reducing afterbody drag. A third configuration of the test van had a truncated boattail to reduce afterbody drag and achieved a drag coefficient of 0.242. These results are included here and references are identified for other means of reducing afterbody drag.