16,136 research outputs found
Numerical methods and a computer program for subsonic and supersonic aerodynamic design and analysis of wings with attainable thrust considerations
This paper describes methodology and an associated computer program for the design of wing lifting surfaces with attainable thrust taken into consideration. The approach is based on the determination of an optimum combination of a series of candidate surfaces rather than the more commonly used candidate loadings. Special leading-edge surfaces are selected to provide distributed leading-edge thrust forces which compensate for any failure to achieve the full theoretical leading-edge thrust, and a second series of general candidate surfaces is selected to minimize drag subject to constraints on the lift coefficient and, if desired, on the pitching moment coefficient. A primary purpose of the design approach is the introduction of attainable leading-edge thrust considerations so that relatively mild camber surfaces may be employed in the achievement of aerodynamic efficiencies comparable to those attainable if full theoretical leading-edge thrust could be achieved. The program provides an analysis as well as a design capability and is applicable to both subsonic and supersonic flow
A computer program for wing subsonic aerodynamic performance estimates including attainable thrust and vortex lift effects
Numerical methods incorporated into a computer program to provide estimates of the subsonic aerodynamic performance of twisted and cambered wings of arbitrary planform with attainable thrust and vortex lift considerations are described. The computational system is based on a linearized theory lifting surface solution which provides a spanwise distribution of theoretical leading edge thrust in addition to the surface distribution of perturbation velocities. The approach used relies on a solution by iteration. The method also features a superposition of independent solutions for a cambered and twisted wing and a flat wing of the same planform to provide, at little additional expense, results for a large number of angles of attack or lift coefficients. A previously developed method is employed to assess the portion of the theoretical thrust actually attainable and the portion that is felt as a vortex normal force
An aerodynamic analysis computer program and design notes for low speed wing flap systems
The expanded capabilities for analysis and design of low speed flap systems afforded by recent modifications of an existing computer program is described. The program provides for the simultaneous analysis of up to 25 pairs of leading-edge and trailing-edge flap deflection schedules. Among other new features of the program are a revised attainable thrust estimation method to provide more accurate predictions for low Mach numbers, and a choice of three options for estimation of leading-edge separation vortex flow effects. Comparison of program results with low speed experimental data for an arrow wing supersonic cruise configuration with leading-edge and trailing-edge flaps showed good agreement over most of the range of flap deflections. Other force data comparisons and an independent study of airfoil and wing pressure distributions indicated that wind-tunnel measurements of the aerodynamic performance of twisted and cambered wings and wings with leading-edge flaps can be very sensitive to Reynolds number effects
The fourier series of gegenbauer's function
Theoretical analysis of Fourier series of Gegenbauer function - methods for integration of Gegenbauer function and Fourier coefficient
Quantum Monte Carlo Calculations of Nuclei
The energies of , , and ground states, the
and scattering states of , the
ground states of , , and and the and
excited states of have been accurately calculated with the Green's
function Monte Carlo method using realistic models of two- and three-nucleon
interactions. The splitting of the isospin and
isospin , multiplets is also studied. The observed
energies and radii are generally well reproduced, however, some definite
differences between theory and experiment can be identified.Comment: 12 pages, 1 figur
Results of a study of the stability of cointegrating relations comprised of broad monetary aggregates
There is strong evidence of a stable “money demand” relationship for MZM and M2 through the 1990s. Though the M2 relationship breaks down somewhere around 1990, evidence has been accumulating that the disturbance is well characterized as a permanent upward shift in M2 velocity that began around 1990 and was largely over by 1994. This paper’s results support the hypothesis that households permanently reallocated a portion of their wealth from time deposits to mutual funds. This reallocation may have been induced by depository restructuring, but it could also be explained by appropriately measured opportunity cost.Demand for money
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