SEARCH · Engineering Papers
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Aerodynamic characteristics obtained in a helical flow environment utilizing a rotary balance located in the Langley spin tunnel are presented in plotted form. The configurations tested included the basic airplane, various control deflections, two canard locations, and wing leading edge modifications, as well as airplane components.
The method of vortex discretization is used to analyze the interaction of the vorticity generated by a strake, with the flow over a delta wing. The validity of the approach is first established by making comparisons with established methods for dealing with delta wings, after which compound delta planforms are discussed. An understanding of the favorable interference effects normally associated with this type of configuration is obtained and results are presented to quantify the expected lift increments resulting from the strake interaction.
Many proposed advanced aircraft - but especially tilt-nacelle, subsonic-cruise, V/STOL aircraft - require nacelles that operate over a wide range of aerodynamic conditions. The optimum design of such nacelles and their inlets is described, including how the inlet low-speed design conditions are selected, the conditions for which the various regions of the inlet are designed, and appropriate criteria of merit. For low-speed operation the optimum internal surface velocity distributions and skin friction distributions are described for three categories of inlets: those without boundary-layer control (BLC), those with BLC, and those with blow-in door slots and retractable slats. Experimental results are presented that show the performance of the various types of inlets. At cruise speed the effect of factors that reduce the nacelle external surface area and the local skin friction is illustrated. These factors are cruise Mach number, inlet throat size, fan-face Mach number, and nacelle contour. The interrelation of these cruise-speed factors with the design requirements for good low-speed performance is discussed. Finally an inlet design without BLC and an optimized inlet design with slots and slats are compared to illustrate the possible reductions in nacelle size.
Wing-leading-edge modifications included leading-edge droop and slat configurations having full-span, partial-span, or segmented arrangements. Other devices included wing-chord extensions, fences, and leading-edge stall strips. Good correlation was apparent between the results of wind-tunnel data and the results of flight tests, on the basis of autorotational stability criterion, for a wide range of wing-leading-edge modifications.
For abstract see A82-30143.
An analysis is presented for calculating the steady three-dimensional flow field in supersonic mixed-compression inlets at incidence. A zonal modeling approach is employed to obtain the solution. The supersonic core flow is computed using a second-order pentahedral bicharacteristic algorithm. The bow shock wave and the reflected internal shock train are determined using a three-dimensional discrete shock fitting procedure. The boundary layer flow adjacent to both the centerbody and the cowl is computed using a second-order implicit finite difference method. The flow in a shock wave-boundary layer interaction region is computed using an integral formulation. The culmination of the present research effort is the development of a production-type computer program capable of analyzing flow in a variety of mixed-compression aircraft inlets. Numerical results and experimental correlations are presented to illustrate application of the analysis.
A nonlinear vortex-lattice method is utilized for the calculation of separated vortex flows over slender bodies at high incidence. Symmetric and asymmetric vortex flow cases are calculated showing good agreement with recently obtained experimental data for an ogive-cyclinder body at high Reynolds numbers. The only input needed for these calculations is the positions of the separation lines on the body. Studies of some of the numerical aspects of this method are described and conclusions are implemented to improve the calculations.
Previously cited in issue 19, p. 2971, Accession no. A82-39113
Previously cited in issue 15, p. 2343, Accession no. A82-31925
Previously cited in issue 13, p. 2021, Accession no. A82-30143
A quantitative evaluation method of the suction effect from a suction plate on side walls is explained. It is found from wind tunnel tests that the wall interference is basically described by the summation form of wall interferences in the case of two dimensional flow and the interference of side walls.
Previously cited in issue 13, p. 2109, Accession no. A82-30152
Previously cited in issue 06, p. 814, Accession no. A82-17862
Previously cited in issue 08, p. 1181, Accession no. A82-22094
Previously cited in issue 5, p. 586, Accession no. A83-16747
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.