The NASA STI Program

Since its founding, NASA has been dedicated to the advancement of aeronautics and space science. The NASA Scientiic and Technical Information (STI) Program OOce plays a key part in helping NASA maintain this important role. The NASA STI Program OOce is operated by Langley Research Center, the lead center for NASA's scientiic and technical information. The NASA STI Program OOce provides access to the NASA STI Database, the largest collection of aeronautical and space science STI in the world. The Program OOce is also NASA's institutional mechanism for disseminating the results of its research and development activities. These results are published by NASA in the NASA STI Report Series, which includes the following report types: TECHNICAL PUBLICATION. Reports of completed research or a major signiicant phase of research that present the results of NASA programs and include extensive data or theoretical analysis. Includes compilations of signiicant scientiic and technical data and information deemed to be of continuing reference value. NASA counterpart and peer-reviewed formal professional papers, but having less stringent limitations on manuscript length and extent of graphic presentations. TECHNICAL MEMORANDUM. Scientiic and technical ndings that are preliminary or of specialized interest, e.g., quick release reports, working papers, and bibliographies that contain minimal annotation. Does not contain extensive analysis. CONTRACTOR REPORT. Scientiic and technical ndings by NASA-sponsored contractors and grantees. CONFERENCE PUBLICATION. Collected papers from scientiic and technical conferences, symposia, seminars, or other meetings sponsored or co-sponsored by NASA. SPECIAL PUBLICATION. Scientiic, technical, or historical information from NASA programs, projects, and missions, often concerned with subjects having substantial public interest. TECHNICAL TRANSLATION. English-language translations of foreign scientiic and technical material pertinent to NASA's mission. Specialized services that complement the STI Program OOce's diverse ooerings include creating custom thesauri, building customized databases, organizing and publishing research results.. . even providing videos. Abstract The performance of an explicit algebraic stress model is assessed in predicting the turbulent ow and forced heat transfer in straight ducts, with square, rectangular, trapezoidal and triangular cross sections, under fully developed conditions over a range of Reynolds numbers. Iso-thermal conditions are imposed on the duct walls, and the turbulent heat uxes are modeled by gradient-diiusion type models. At high Reynolds numbers (> 10 5), wall functions are used for the velocity and temperature elds, while at low Reynolds numbers, damping functions are introduced into the models. Hydraulic parameters such as friction factor and Nusselt number are well …