摘 要:Phillips 谱是海浪实时绘制中常用的波浪谱。首先分析了Phillips 谱的结构,#br# 指出该谱是一个瞬时空间谱,其频率谱符合Neumann 形式,与P-M 谱接近,其方向分布函#br# 数为国际拖曳水池会议推荐的形式。令P-M 谱与Phillips 谱具有相同的单位面积波能,给出#br# 了Phillips 谱风速的确切含义并计算出该谱的常数。除了使用Phillips 谱,还尝试其它形式#br# 的谱。用P-M 谱和cos-2s 形式方向分布函数构造了瞬时空间谱PM-cos2s 形式,用JONSWAP#br# 谱和Poisson 形式方向分布函数构造了瞬时空间谱J-Po 形式。比较3 种谱的绘制结果发现,#br# 使用Phillips 谱、PM-cos2s 谱的绘制结果均能反映风速对海浪的影响,不能反映风距的影响,#br# 使用J-Po 谱的绘制结果既能反映风速、也能反映风距对海浪的影响,且三者的绘制帧率一#br# 致。如果要选择适合航海模拟器中海浪绘制的瞬时空间谱,该谱的风参数既应包括风速,也#br# 应包括风距,且生成波应在风向的(-?,?]范围内,因此J-Po 谱在三者中最适合航海模拟器。#br# 绘制结果已应用于航海模拟器中。#br# 关 键 词:海浪绘制;Phillips 波浪谱;方向分布函数;风速
Abstract: The Phillips spectrum is widely used in ocean wave real-time rendering. First, the#br# structure of the spectrum is analyzed. The Phillips spectrum is an instantaneous spatial spectrum.#br# Its frequency spectrum is in accord with the spectrum form raised by Neumann and similar to the#br# P-M spectrum. Its directional distribution function is that recommended by the international#br# towing tank conference. On the hypothesis that the wave energy per unit area of the Phillips#br# spectrum equals that of the P-M spectrum, the spectral constant is computed, and the spectral wind#br# speed is clarified. In addition to the Phillips spectrum, other spectra are tried as well. The P-M#br# spectrum and the directional distribution function of cos-2s form are used to construct an#br# instantaneous spatial spectrum, denoted as PM-cos2s form, and the JONSWAP spectrum and the#br# direction distribution function of Poisson form are applied for constructing an instantaneous#br# spatial spectrum, denoted as J-Po from. The comparison of the rendering results of the three#br# spectra shows that the wave rendered with the Phillips spectrum and PM-cos2s spectrum can#br# reflect wind speed influence on the wave, but cannot embody the fetch length influence, while the#br# wave rendered with J-Po spectrum can show the fetch length effect along with wind speed on the wave. With the same computer hardware, the frame rates of the three spectra are equal. For wave#br# rendering in the nautical simulator, the wind parameter of the selected spectrum should contain the#br# wind speed as well as fetch length, and the generated wave of the spectrum should distribute in#br# (-?,?] of the wind speed. So J-Po spectrum is more suitable than the other two for the nautical#br# simulator. The method was used in the nautical simulator.#br# Key words: ocean wave rendering; Phillips spectrum; directional distribution function; wind#br# speed
摘要: Phillips 谱是海浪实时绘制中常用的波浪谱。首先分析了Phillips 谱的结构,
指出该谱是一个瞬时空间谱,其频率谱符合Neumann 形式,与P-M 谱接近,其方向分布函
数为国际拖曳水池会议推荐的形式。令P-M 谱与Phillips 谱具有相同的单位面积波能,给出
了Phillips 谱风速的确切含义并计算出该谱的常数。除了使用Phillips 谱,还尝试其它形式
的谱。用P-M 谱和cos-2s 形式方向分布函数构造了瞬时空间谱PM-cos2s 形式,用JONSWAP
谱和Poisson 形式方向分布函数构造了瞬时空间谱J-Po 形式。比较3 种谱的绘制结果发现,
使用Phillips 谱、PM-cos2s 谱的绘制结果均能反映风速对海浪的影响,不能反映风距的影响,
使用J-Po 谱的绘制结果既能反映风速、也能反映风距对海浪的影响,且三者的绘制帧率一
致。如果要选择适合航海模拟器中海浪绘制的瞬时空间谱,该谱的风参数既应包括风速,也
应包括风距,且生成波应在风向的(-,]范围内,因此J-Po 谱在三者中最适合航海模拟器。
绘制结果已应用于航海模拟器中。