36 results about "Propagation equation" patented technology

The invention provides an elastic wave least squares inverse time migration method based on an acoustic-elastic coupling equation. The method comprises the steps of: firstly, inputting an initial longitudinal and horizontal wave velocity and a density initial model, synthesizing a shot end forward propagation wave field and a detection end reverse propagation wave field by using an acoustic-elastic coupling propagation equation and an accompanying equation thereof, and figuring out a multi-parameter image according to the imaging conditions of the longitudinal and horizontal wave velocity anddensity; then, synthesizing reflected wave data by back migration according to a first-order Bonn scattering equation of the acoustic-elastic coupling equation; and evaluating the imaging result according to a four-component waveform residual objective function, if the imaging result is not satisfied, iteratively updating the longitudinal and horizontal wave velocity and density imaging results byusing a CGLS algorithm of a diagonal Hessian precondition, until the condition is satisfied, and returning a final result.

The invention provides a noise prediction and layout optimization method for a flat terrain wind power plant. The noise prediction and optimization layout method for the flat terrain wind power plantcomprises the following steps that 1, on the basis of a wind power plant engineering wake flow model, generating the incoming flow wind speed of each wind turbine in the wind power plant, and calculating the aerodynamic noise source of each wind turbine; 2, simplifying the three-dimensional PE parabolic equation, and calculating a wind turbine noise propagation database based on a two-dimensionalnoise propagation equation of a single wind turbine; Step 3, according to the wind turbine noise propagation database obtained in the step 2, carrying out wind power plant noise numerical simulation calculation by using a wind power plant noise propagation multidimensional interpolation formula; And 4, optimizing the optimized layout of the wind power plant meeting the sound pressure level contourline by adopting a maximum sound pressure boundary value taking method.

The invention discloses a level set topology optimization method, system, equipment and medium, belonging to the field of structure design topology optimization. and the boundary propagation equation; respectively perform spatial smoothing filtering and time smoothing filtering on the strain energy density of each finite element element, and update the value of the Lagrange multiplier in the boundary propagation equation to the Nth after filtering s A small strain energy density, N s is the number of solid finite element elements to be removed at present; topology optimization is performed based on the updated boundary propagation equation and level set function to reduce the flexibility of the design area; the above calculation, filtering, updating and optimization operations are repeated until the optimization is completed. The flexibility of the design region converges to a minimum. A parameter-free method is proposed to determine Lagrange multipliers, which can effectively solve the problems of inaccurate volume constraints, low computational efficiency and unstable convergence of existing methods.

The invention discloses a particle filter multi-crack propagation prediction method based on the number of dynamic cracks, which belongs to the technical field of fault prediction and health management. The invention adopts the online guided wave structure health monitoring method to monitor the initiation and propagation of cracks in the structure online. When a new crack initiation is detected, the crack components and the number of crack propagation equations in the multi-crack propagation state equation are updated, and the cracks under multi-crack coupling are constructed. Extend the law, and update the particle set. Combined with the online observations obtained by the guided wave structural health monitoring method, the posterior probability density function of the multi-crack propagation state vector is estimated online by regularized particle filter. The crack growth model is updated by the posterior estimation of the model parameters, and the trajectory of each crack growth in the future is predicted from the posterior estimation of the crack length. The invention can effectively realize the on-line monitoring and prediction of multiple cracks in the structure, and has wide application prospects in the prediction of the expansion of multiple cracks in the structure.

The invention relates to a spacecraft robust rendezvous trajectory design method considering uncertain factors. With utilization of the characteristic of constructing an uncertain factor propagation equation rapidly and precisely according to a covariance analysis method, influences on a nominal track by uncertain factors are analyzed. A robust optimization problem is constructed by using the analysis results as the constraints of the optimization problem. Calculation is carried out based on a genetic algorithm to realize the robust rendezvous trajectory design. Therefore, the traditional optimal system rendezvous determination problem is transformed into a robust rendezvous problem considering uncertain factors; and calculation is carried out based on the genetic algorithm, so that an objective of the robust rendezvous trajectory design is achieved.

The embodiment of this specification discloses a pure qP wave least squares reverse time migration imaging method in a TTI medium. The present invention obtains the forward wave field at each moment through the pure qP wave forward equation of the viscoacoustic TTI medium, and then obtains the backpropagation wave field at each moment through the pure qP wave backpropagation equation of the viscoacoustic TTI medium, and then uses the mutual Relevant imaging conditions were used to obtain the reverse time migration imaging results. Compared with the prior art, the present invention can obtain imaging results with amplitude fidelity and higher imaging resolution when the subterranean medium has viscous and strong anisotropic properties.

The invention discloses a method for calculating the interference of a point source radiation field on a cable in an infinitely large shielding layer with a hole. It is applied to the field of electromagnetic interference and has the advantages of simple algorithm, accurate results, and high efficiency. The invention uses the voltage on the cable The wave propagation channel and the space electromagnetic field propagation channel are represented by signal pipes, and the positions with energy reflection are represented by nodes, and the signal flow diagram reflecting the electromagnetic energy flow of the system is established, and the magnetic flow element radiation is used instead of the small hole transmission to establish the whole The propagation equation on the signal pipeline of the system and the scattering equation on all nodes are synthesized to obtain the extended BLT (Baum‑Liu‑Tesche) equation of the system electromagnetic interference, and the extended BLT equation is solved to obtain the interference intensity on the cable to achieve point-to-point The accurate calculation of the electromagnetic interference that the source radiation field couples to the transmission line through the infinite shielding layer with holes effectively reduces the dependence on computing resources and improves the efficiency.