【摘要】：畸形波是海洋中一類特殊的災害性波浪,隨著人類海上活動的增加,畸形波對船舶以及海洋平臺等結構物的破壞越來越多,逐漸引起了人們的重視,但由于畸形波本身的復雜性,并且真正完整的觀測記錄也相對較少,至今畸形波的生成機理和基本特性等,尤其是關于畸形波的發(fā)生概率仍然不是十分明確,雖然很多學者也進行了大量的研究,并取得了相應的成果,但大部分都是基于二維波浪,而實際的海浪是三維的,不僅有不同頻率的組成波,還有不同方向的組成波。因此,本文對多向不規(guī)則隨機波列中畸形波的發(fā)生概率及影響因素等開展了研究。 本文考慮了不同方向分布和相對水深的影響,對多向不規(guī)則波列進行了長時間的物理模擬。對多向不規(guī)則波列的統(tǒng)計參數(shù)(如有效波高、偏度、峰度和頻譜)以及波高、波峰和波谷的概率分布進行了分析,并研究了波陡、方向分布和相對水深等參數(shù)對波列統(tǒng)計參數(shù)和概率分布的影響。研究結果表明：1.波浪的方向分布和相對水深對波列的統(tǒng)計參數(shù)有明顯的影響,當相對水深較大,方向分布較窄時,由于波浪的非線性不穩(wěn)定性,峰度值隨著波浪的傳播,有逐漸增大的趨勢,波列的頻譜出現(xiàn)主頻下移,高頻能量減小等現(xiàn)象；當相對水深較淺時,波浪的不穩(wěn)定性受到抑制,峰度值隨波浪的傳播變化不大,頻譜的主頻甚至出現(xiàn)上移。2.波浪的方向分布和水深也會影響到波高、波峰和波谷的概率分布,當相對水深較大,方向分布較窄時,由于波浪的非線性不穩(wěn)定性,波高、波峰和波谷的概率分布末端越增大,并隨著波浪的傳播而明顯增大；對于淺水情況,不穩(wěn)定性受到抑制,二階非線性起到主要作用,方向分布的變化對波高、波峰和波谷的概率分布影響不如深水時明顯。3.從不同的方向分布生成的畸形波的實驗過程中可以看出,當波浪越趨于單向的時候,則畸形波的生成更多的是基于波浪自身的不穩(wěn)定性自聚焦而成,而當波浪的方向分布較大,特別是趨于均勻分布的時候,畸形波的生成則更多的是基于波浪之間的匯聚而成。 本文通過對多向不規(guī)則波列中統(tǒng)計參數(shù)和概率分布的分析,可以得出,當相對水深較深,方向分布較窄時,由于波浪的不穩(wěn)定性,大波高的出現(xiàn)概率增大,因此,畸形波更容易出現(xiàn)在這種海況下,海上結構物設計時,應充分考慮到海況對波高分布的影響。
[Abstract]:Deformed waves are a special kind of disastrous waves in the ocean. With the increase of human activities at sea, the damage of deformities to ships and structures such as offshore platforms is becoming more and more serious, and people pay more and more attention to them. However, due to the complexity of the deformity wave itself and the relatively few truly complete observation records, so far the formation mechanism and basic characteristics of the deformity wave, especially about the occurrence probability of the deformed wave, are still not very clear. Although many scholars have done a lot of research and obtained corresponding results, most of them are based on two-dimensional waves, but the actual waves are three-dimensional, not only have different frequencies of the component waves, but also in different directions. Therefore, in this paper, the occurrence probability and influencing factors of abnormal waves in multidirectional irregular random wave trains are studied. In this paper, the effects of different direction distribution and relative water depth are considered, and a long time physical simulation of multidirectional irregular wave train is carried out. The statistical parameters (such as effective wave height, deviation, kurtosis and spectrum) and the probability distribution of wave height, peak and trough of multidirectional irregular wave train are analyzed, and the wave steepness is studied. The influence of direction distribution and relative water depth on the statistical parameters and probability distribution of wave train. The results of the study show that 1: 1. The directional distribution of wave and the relative water depth have obvious influence on the statistical parameters of wave train. When the relative water depth is larger and the direction distribution is narrower, because of the nonlinear instability of the wave, the kurtosis value increases gradually with the wave propagation. When the relative water depth is shallow, the wave instability is restrained, the kurtosis value changes little with the wave propagation, and the main frequency of the frequency spectrum even moves up. 2. The directional distribution and water depth of wave also affect the probability distribution of wave height, wave peak and trough. When the relative water depth is larger and the direction distribution is narrower, the higher the wave height, the more the probability distribution end of wave peak and trough is due to the nonlinear instability of wave. For shallow water, the instability is restrained, the second order nonlinearity plays a major role, and the variation of directional distribution has less effect on the wave height, the probability distribution of wave peaks and troughs than that of deep water. It can be seen from the experimental process that the abnormal waves generated in different directions tend to be generated on the basis of the instability of the wave itself when the wave tends to be unidirectional, but when the direction distribution of the wave is larger, the formation of the deformable wave is mainly based on the instability of the wave itself. Especially when it tends to uniform distribution, the formation of abnormal waves is more based on the convergence of waves. Through the analysis of the statistical parameters and probability distribution in multidirectional irregular wave trains, it can be concluded that when the relative water depth is deeper and the direction distribution is narrower, the occurrence probability of large wave height increases due to wave instability. Deformed waves are more likely to occur in such sea conditions, and the influence of sea conditions on wave height distribution should be fully taken into account in the design of offshore structures.
【學位授予單位】：大連理工大學
【學位級別】：碩士
【學位授予年份】：2014
【分類號】：P731.2

【參考文獻】

相關期刊論文 前8條

1 陶愛峰;鄭金海;MEE Mee Soe;陳波濤;;Re-study on Recurrence Period of Stokes Wave Train with High Order Spectral Method[J];China Ocean Engineering;2011年04期

2 高璞;汪留松;趙西增;;畸形波特性研究[J];中國港灣建設;2007年06期

3 李金宣;李鵬飛;柳淑學;;Observations of Freak Waves in Random Wave Field in 2D Experimental Wave Flume[J];China Ocean Engineering;2013年05期

4 胡金鵬;張運秋;朱良生;;基于Benjamin-Feir不穩(wěn)定性的畸形波模擬[J];華南理工大學學報(自然科學版);2009年06期

5 高志一;于福江;許富祥;李本霞;李潔;郎姝燕;;畸形波生成條件預報方法研究進展[J];海洋通報;2011年03期

6 趙西增;孫昭晨;梁書秀;;高階譜方法建立三維畸形波聚焦模擬模型[J];海洋工程;2009年01期

7 王瑤;鄭金海;陶愛峰;陳波濤;;基于實測資料的畸形波發(fā)生概率研究綜述[J];海洋通報;2013年02期

8 周亞龍;鄒志利;;無風條件下馬蹄波波面演化特征的實驗研究[J];力學學報;2010年01期

，

本文編號：2190654