【摘要】：海浪譜是描述海浪過程的基本特征參數(shù)。利用譜描述海浪并獲得海浪要素具有重要的理論和實(shí)用意義。海浪觀測與分析、海浪預(yù)報(bào)、海洋環(huán)境研究、造船與水港工程等都需要結(jié)合海浪譜進(jìn)行,海浪譜是目前海浪研究的中心問題之一。由于海浪本身的復(fù)雜性,小部分海浪譜是由觀測到的波要素連同某些假定推導(dǎo)而來,大部分海浪譜則是利用定點(diǎn)波面記錄通過特殊譜分析方法得到。國內(nèi)外已有的諸多對譜分析方法的研究都是對采樣特征以及譜估計(jì)參量利用控制變量法進(jìn)行單獨(dú)討論,并沒有考慮二者之間可能存在的關(guān)系,且由于之前的研究討論一般都是基于現(xiàn)場實(shí)測海浪數(shù)據(jù),因此也未能分析目標(biāo)靶譜對譜估計(jì)結(jié)果可能造成的影響�；诖�,本文進(jìn)行了相關(guān)的研究計(jì)算。本文通過對具有不同特征目標(biāo)靶譜,在不同的采樣特征條件下由線性波浪疊加的方法生成的多組隨機(jī)波面應(yīng)用不同的譜分析方法進(jìn)行譜分析計(jì)算,并用估計(jì)精度衡量了估計(jì)譜結(jié)果相對于靶譜的估計(jì)效果,得到了不同參量條件下對應(yīng)的估計(jì)精度曲線,計(jì)算分析了不同特征量對FTA法,Welch法,AR模型法譜分析的影響。結(jié)果表明影響譜估計(jì)效果的因素不只有譜估計(jì)方法的參量以及采樣特征量,所要研究的目標(biāo)海浪譜的特征同樣在一定程度上決定著能否得到有效的估計(jì)譜結(jié)果。有可能出現(xiàn)FTA法的最大推移乘積數(shù),Welch法的分段數(shù),以及AR模型的階數(shù)無論如何變化,都得不到滿意的譜估計(jì)結(jié)果的情況。而在各特征參量選值合適的情況下,三種方法都可以取得滿意的結(jié)果。其中,目標(biāo)靶譜譜寬對Welch法以及AR模型法的精度曲線分布影響較大,對FTA法估計(jì)效果影響較小。譜峰尖度則對三種譜估計(jì)方法均有影響,其中AR模型法對譜峰尖度比較大的目標(biāo)靶譜的估計(jì)穩(wěn)定性較好,而FTA法和Welch法則只在譜峰尖度較小時(shí)估計(jì)效果較好。采樣時(shí)長對Welch法以及AR模型法的穩(wěn)定性影響并不顯著,且采樣時(shí)長與最優(yōu)段數(shù)與模型階數(shù)之間還存在一定的數(shù)值關(guān)系。采樣時(shí)長的減小會(huì)導(dǎo)致FTA譜估計(jì)的穩(wěn)定性下降。采樣頻率在滿足奈奎斯特采樣頻率的前提下,對FTA法與Welch法沒有顯著影響,而AR模型法的最優(yōu)階數(shù)與采樣頻率之間存在某種數(shù)值關(guān)系。
[Abstract]:Wave spectrum is the basic characteristic parameter to describe the wave process. It is of great theoretical and practical significance to use spectrum to describe waves and obtain wave elements. Wave observation and analysis, wave prediction, marine environment research, shipbuilding and water port engineering all need to be combined with wave spectrum. Wave spectrum is one of the central problems in wave research at present. Because of the complexity of the wave itself, a small part of the wave spectrum is derived from the observed wave elements together with some assumptions, and most of the wave spectrum is obtained by the special spectral analysis method by using the fixed-point wavefront records. Many existing studies on spectral analysis methods at home and abroad discuss the sampling characteristics and spectral estimation parameters separately by using the control variable method, and do not consider the possible relationship between the two methods. Because the previous research and discussion are generally based on the measured wave data, it is not possible to analyze the possible influence of the target spectrum on the spectral estimation results. Based on this, the related research and calculation are carried out in this paper. In this paper, the spectral analysis of multiple groups of random wavefront generated by linear wave superposition method under different sampling characteristics is carried out by using different spectral analysis methods for the target spectrum with different characteristics. The estimation effect of the estimated spectrum results relative to the target spectrum is measured by the estimation accuracy, and the corresponding estimation accuracy curves under different parameters are obtained. The effects of different characteristic quantities on the spectral analysis of FTA method, Welch method and AR model method are calculated and analyzed. The results show that the factors that affect the spectral estimation effect are not only the parameters of the spectral estimation method and the sampling characteristics, but also the characteristics of the target sea wave spectrum to a certain extent determine whether the effective estimation spectrum results can be obtained. It is possible that the maximum moving product of FTA method, the piecewise number of Welch method and the order of AR model can not get satisfactory spectral estimation results. Under the condition that each characteristic parameter is suitable, all three methods can obtain satisfactory results. Among them, the spectral width of the target has a great influence on the accuracy curve distribution of the Welch method and the AR model method, but has little effect on the estimation effect of the FTA method. The spectral peak cusp has an influence on all three spectral estimation methods, among which the AR model method has better stability in the estimation of the target spectrum with large spectral peak cusp, while the FTA method and Welch rule have better estimation effect only when the spectral peak cusp is small. The sampling time has no significant effect on the stability of Welch method and AR model method, and there is still a certain numerical relationship between the sampling time and the optimal number of segments and the order of the model. The decrease of sampling time will lead to the decrease of the stability of FTA spectrum estimation. On the premise of satisfying the Nyquist sampling frequency, the sampling frequency has no significant effect on the FTA method and the Welch method, but there is a numerical relationship between the optimal order of the AR model method and the sampling frequency.
【學(xué)位授予單位】：大連理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2016
【分類號】：P731.22

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 許景波;邊信黔;付明玉;;長峰波海浪的數(shù)值模擬仿真與頻譜估計(jì)[J];哈爾濱理工大學(xué)學(xué)報(bào);2010年04期

2 張峰;石現(xiàn)峰;張學(xué)智;;Welch功率譜估計(jì)算法仿真及分析[J];西安工業(yè)大學(xué)學(xué)報(bào);2009年04期

3 羅敏;劉嵩;;基于Welch算法的功率譜估計(jì)的實(shí)現(xiàn)[J];北京工商大學(xué)學(xué)報(bào)(自然科學(xué)版);2007年03期

4 楊惠珍,康鳳舉,褚彥軍,聶衛(wèi)東;基于海浪譜的隨機(jī)海浪仿真及驗(yàn)證[J];系統(tǒng)仿真學(xué)報(bào);2005年10期

5 王曉峰,王炳和;周期圖及其改進(jìn)方法中譜分辨率的MATLAB分析[J];武警工程學(xué)院學(xué)報(bào);2003年06期

6 管長龍;我國海浪理論及預(yù)報(bào)研究的回顧與展望[J];青島海洋大學(xué)學(xué)報(bào)(自然科學(xué)版);2000年04期

7 陳國平,喬樹梁,杜金曼,鄒山;最大熵法風(fēng)浪譜估計(jì)[J];水利水運(yùn)科學(xué)研究;1999年02期

8 吉培榮,何振亞;最大熵譜模型的定階及譜值快速計(jì)算[J];武漢水利電力大學(xué)(宜昌)學(xué)報(bào);1997年01期

9 鄭兆瑞, 楊友堂;最大熵譜估計(jì)中的譜峰幅度及分辨率[J];系統(tǒng)工程與電子技術(shù);1995年06期

10 李陸平;海浪譜估計(jì)最優(yōu)設(shè)計(jì)平穩(wěn)海浪過程[J];海洋與湖沼;1988年03期

相關(guān)會(huì)議論文 前1條

1 婁峰;楊慶;欒茂田;張大林;;時(shí)間序列AR模型定階準(zhǔn)則的改進(jìn)方法[A];巖石力學(xué)新進(jìn)展與西部開發(fā)中的巖土工程問題——中國巖石力學(xué)與工程學(xué)會(huì)第七次學(xué)術(shù)大會(huì)論文集[C];2002年

，

本文編號：2491995