helmholtz wave 中文意思是什麼
helmholtz wave
解釋
亥姆霍茲波；黑目合茲波-
Base on helmholtz integral equation, the incoherent scattering of plane wave from rough cone - shaped surface is derived with the far field theory and stationary phase method. and the incoherent scattering of plane wave from rough conical surface is also derived with shadowing function when the the radius of principal
最後計算並分析了入射光為= 0 . 48 m時，粗糙錐面的平面波散射特性，考察了入射波和散射波的幾何關系，偏振態以及粗糙面統計參量等對散射強度的影響。 -
In this dissertation, the numerical computation for the acoustic radiation problem ( arp ) is studied deeply and systematically in the theory, method and the application technique, based on analyzing the situation of the home and abroad on the numerical computation for the acoustic radiation problem. the calculation formulas of the boundary element method ( bem ) for the exterior acoustic radiation problem in the full - space and half - space are deduced, based on the wave propagation theorem ; the arising of the non - unique solutions, which is associated with the application of the boundary integral equation ( bie ) in acoustic radiation problem, is analyzed and proofed ; the improved combined helmholtz integral equation formulation ( ichief ) is presented to overcome the non - uniqueness problem more effectively and reliably ; the determination of the singular integral coefficients on various occasions is analyzed ; the properties and treatments of the singular integrals with different orders axe studied ; the computation program of the cubic spline ichief is developed and its ability to overcome the non - uniqueness problem and feasibility to discrete the surface coarsely with the sufficient calculation precision are examined through examples
第二章在聲波動理論基礎上，詳細地推導出對應于無限域和半無限域的外部振動聲輻射問題的邊界積分方程計算公式；根據fredholm積分理論，對利用邊界積分方程計算振動聲輻射問題過程中解的非唯一性的產生進行了分析和證明；改進了chief法以提高其克服解的非唯一性的有效性和可靠性；對不同條件下奇性系數的計算、強奇性積分的收斂性及其在變量替換時與普通積分的差異性、不同階奇性積分的計算、數值求積分等進行了研究；開發了三次樣條改進chief法計算軟體，並通過算例考核了該方法在特徵波數處克服解的非唯一性的有效性和在保證計算精度的前提下實現剖分粗化以提高計算效率的可行性。 -
Essential to their utility is the requirement that the evolution of the basic functions through the propagation environment constitutes a simplified problem with an exact or approximate closed form solution to the original wave equation. the evolution of a spatial fourier harmonic through a homogeneous medium is governed by a reduced wave equation, obtained by applying the fourier transform to the helmholtz equation, with a simple and well - known solution - the plane wave
這些方法均採用一組具有全局特性的基本函數對波場進行分解，如占據整個空間的富氏調諧函數或充滿各個方向的dirac函數（點源） ，並通過求解基本函數滿足波動方程的精確解或近似解來達到波場外推的目的。
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