6 results about "Linear algebraic equation" patented technology

The application provides a sound flow coupling calculation method and device based on a Galbrun equation. The method provided by the application comprises the following steps: obtaining a Galbrun equation based on Euler equations of an ideal fluid under no external force, in combination with Euler disturbance, Lagrange disturbance and mixed disturbance relationship; the Galbrun equation represents the coupling effect of a flow field and a sound field; obtaining flow field data of a non-uniform flow field based on Navier-Stokes equations, in combination with a k-ε turbulence model in a RANS model; introducing a perfect matched layer for sound wave propagation simulation in an unbounded region, and constructing boundary conditions suitable for the Galbrun equation through geometric transformation, complex variable definition and coordinate conversion; performing weak transformation on the Galbrun equation, embedding the boundary conditions, combining the flow field data, adopting triangular finite elements for discretization processing, constructing a global linear algebraic equation group and solving, and obtaining discrete solutions of sound field parameters.

The invention provides an acoustic streaming coupling calculation method and device based on a Galbrun equation. The method provided by the invention comprises the steps of obtaining a Galbrun equation based on an Euler equation of ideal fluid under the condition of no external force and in combination with Euler disturbance, Lagrange disturbance and a mixed disturbance relation; the Galbrun equation represents the coupling effect of the flow field and the sound field; based on a Navier-Stokes equation, in combination with a k-epsilon turbulence model in the RANS model, solving to obtain flow field data of the non-uniform flow field; a perfect matching layer is introduced for sound wave propagation simulation of an unbounded region, and boundary conditions suitable for the Galbrun equation are constructed through geometric transformation, complex variable definition and coordinate transformation; and carrying out weak transformation on the Galbrun equation, embedding the boundary condition, combining the flow field data, carrying out discretization processing by adopting a triangular finite element, constructing a global linear algebraic equation set, and solving to obtain a discrete solution of sound field parameters.

The application discloses a kind of inland lake ecological water supplement amount prediction analysis method, comprising: obtaining the underwater topographic map of target lake, constructs the plane two-dimensional water flow movement basic equation of lake wind lake current and the plane two-dimensional water quality equation describing salt transport in lake conversion;Obtain the ecological water supplement flow and salt concentration of target lake, fit the plane two-dimensional water quality equation;To the finite difference discrete of continuity equation, momentum equation, the plane two-dimensional water flow movement basic equation is converted into linear algebra equation group;Linear algebra equation group is solved by ADI row-by-row method in time period, direction, and the water level, water depth and salt concentration of output prediction are exported;The water depth of each grid ecological water supplement is calculated, and then the comprehensive water depth of target lake ecological water supplement in future time is calculated, and the ecological water supplement amount of target lake prediction is obtained.

This invention relates to the field of capacitance calculation technology and discloses a fast algorithm for extracting parasitic capacitance in large-scale integrated circuits. This method combines the method of moments (MoM), a fast multipole algorithm for layered dielectrics, and overlapping region decomposition preprocessing techniques to construct a complete parasitic capacitance extraction solution. By directly introducing the Green's function for the layered dielectric, the numerical solution strictly satisfies the electric field transport conditions at the dielectric interface, and the electrostatic problem in the layered dielectric is transformed into boundary integral equations defined on the interconnect surface. Subsequently, the MoM is used to discretize these boundary integral equations, resulting in a large-scale dense system of linear algebraic equations. To improve solution efficiency, an efficient preprocessing strategy based on overlapping region decomposition is further designed, and combined with the matrix-free minimum residual iteration method and the layered fast multipole algorithm, achieving efficient solution with low computational and storage overhead.

The application discloses a kind of power grid to buried pipe network's electromagnetic interference calculation method, comprising the following steps: conductor is divided into a conductor microsection, conductor microsection outer surface two end potential difference is equal to the potential difference of conductor microsection inside, according to this continuity feature equation group is established, according to leakage current the potential difference of conductor microsection outer surface two ends is solved, the impedance of conductor microsection itself and the product of axial current are then solved the potential difference of conductor microsection inside two ends;According to Kirchhoff's law, the relationship between axial current and leakage current on each conductor microsection is obtained, a set of linear algebraic equations is established, and the leakage current distribution on the conductor is obtained by solving the linear algebraic equations.The results of the application are used to evaluate the influence of electromagnetic interference on buried pipe network, so as to control the risk in advance and realize the harmonious coexistence of power grid and oil and gas pipeline network.

This invention belongs to the field of hypersonic aerodynamics and discloses a method for predicting hypersonic boundary layer transition based on the numerical solution of the frequency domain Navier-Stokes equations. This method, through the assumption of small perturbations, linearly decomposes the hypersonic flow field into a steady flow field and a perturbed flow field. It eliminates the time differential terms in the time-domain Navier-Stokes equations using complex decomposition, transforming the time-domain Navier-Stokes equations into linear algebraic equations in complex space, thereby simplifying the solution and analysis of the time-domain Navier-Stokes equations. Specifically, it includes three stages: preprocessing, solver, and post-processing. The iterative solution of the frequency-domain Navier-Stokes equations in the solver is the core, including spatial discretization of the frequency-domain Navier-Stokes equations, iterative progression, implementation of boundary conditions, parallel data exchange, convergence judgment, and result output. The hypersonic boundary layer transition prediction method based on the numerical solution of the frequency-domain Navier-Stokes equations of this invention can balance computational efficiency and accuracy, and has practical engineering value.