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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.
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Point-kernel radiation shielding computer program to evaluate propellant heating and dose to crew during engine operation
Integral transformation with Whittaker kernel functions
Abstract reproducing kernel Hilbert spaces /RKHS/, applying basic properties to band limited signals study
Approximation for discretization error of discrete analog of Bergman harmonic kernel, discussing discretization error in Dirichlet and Neumann problems for Laplace equation
Solution smoothness of Volterra integral equations with weakly singular kernels
Radiation shield design and transport calculations, reviewing kernel methods development and relevant computer programs
Flutter analysis for thin lifting surfaces by application of supersonic kernel function procedure
Point kernel techniques for use with nuclear rocket shielding methods, modification, updating, and input data preparation - Vol. 6
Polyvinyl chloride nonlinear viscoelastic behavior by multiple integral representation, determining kernel functions for mixed time parameters from tension/torsion creep experiments
Differentiability of nonlinear Volterra integral equations of second kind with convolutional weakly singular kernels
Kernel function for nonplanar oscillating surfaces in supersonic flow, using finite element method for interfering configurations
A point matrix kernel for radiation transport, developed by the transmission matrix method, has been used to develop buildup factors and energy spectra through slab layers of different materials for a point isotropic source. Combinations of lead-water slabs were chosen for examples because of the extreme differences in shielding properties of these two materials.
The method of Fourier transforms is used to determine the kernel function which relates the pressure on a lifting surface to the prescribed downwash within the framework of Dowell's (1971) shear flow model. This model is intended to improve upon the potential flow aerodynamic model by allowing for the aerodynamic boundary layer effects neglected in the potential flow model. For simplicity, incompressible, steady flow is considered. The proposed method is illustrated by deriving known results from potential flow theory.
A function integral equation governing the unsteady motion of a supersonic cascade is derived. Various representations of the Kernel function are derived and discussed.
The theory, results and user instructions for an aerodynamic computer program are presented. The theory is based on linear lifting surface theory, and the method is the kernel function. The program is applicable to multiple interfering surfaces which may be coplanar or noncoplanar. Local linearization was used to treat nonuniform flow problems without shocks. For cases with imbedded shocks, the appropriate boundary conditions were added to account for the flow discontinuities. The data describing nonuniform flow fields must be input from some other source such as an experiment or a finite difference solution. The results are in the form of small linear perturbations about nonlinear flow fields. The method was applied to a wide variety of problems for which it is demonstrated to be significantly superior to the uniform flow method. Program user instructions are given for easy access.
This paper presents a FORTRAN program written to solve for the kernel of a matrix of polynomials with real coefficients. It is an implementation of Sain's free modular algorithm for solving the minimal design problem of linear multivariable systems. The structure of the program is discussed, together with some features as they relate to questions of implementing the above method. An example of the use of the program to solve a design problem is included.
A logarithmic-singularity correction factor is derived for use in kernel function methods associated with Multhopp's subsonic lifting-surface theory. Because of the form of the factor, a relation was formulated between the numbers of chordwise and spanwise control points needed for good accuracy. This formulation is developed and discussed. Numerical results are given to show the improvement of the computation with the new correction factor.