離岸風機運轉噪音模擬分析

本研究重點在於針對離岸風機的運轉噪音進行影響評估與模擬分析，現今大部分文獻研究對於離岸風機的運轉噪音研究集中在量測，並依據量測結果與相關風機參數結果推展出依離岸風機設計功率、風速、距離等參數所相對應的運轉噪音。但此種模式有部分疑慮，由於目前離岸風機有需多種不同的基樁種類，固定式基礎就分為單樁、套筒、三腳與重力式，而浮式風機分為張力腿、半浮潛與圓筒式，而這些種類又都有相對應的不同參數，這些參數皆會影響到運轉噪音的大小，僅僅是風機的額定功率影響最大。因此本研究將依據現今台灣評估離岸風機打樁噪音的方式，依循一套聲源由有限元素法進行模擬，並使用拋物線音傳方程式，計算離岸風機運轉噪音傳遞至遠場距離的噪音大小，此方法流程目前被廣泛應用於離岸風機的打樁噪音評估。本研究將會主要分成三大部分，噪音影響、模擬結果與離岸浮式風機模擬。噪音影響部分會回顧離岸風機相關的噪音，再對運轉噪音之噪音特性進行整理，最後將會是統整該噪音會對海域生物所造成的影響。而模擬結果將分為三個階段，驗證輸入函數、固定式基礎實際案例對比與浮式風機實際案例對比，本研究將藉由此三種案例驗證該方法的可行性與準確性。本研究所使用的方法可以解決一定程度上用量測案例統計回歸之預測模型的疑慮，並讓吾人在未來面對評估離岸風機的運轉噪音影響時有所依據。本研究雖然可以預測模擬分析離岸風機的運轉噪音，但也有相關無法處理的狀況，在處理複數風機所造成的影響時，此種方法較費時且成本較高。在對應到以上此種狀況時，可使用模擬結果進行變異數分析及迴歸分析，回歸出可適用的離岸風機運轉噪音公式，如同本研究回歸出的結果。然而本研究回歸出之結果有一定限制，若是遇到不同種類的底質環境與參數超出範圍，則須重新進行模擬及統計分析。除此之外，本研究所使用之案例風機設計功率都在6MW以下，在未來應對大功率的離岸風機時仍需額外的驗證。

關鍵字

離岸風機；離岸浮式風機；運轉噪音；有限元素法；風機震動函數

並列摘要

This study focus on the impact and simulation analysis of the offshore wind turbines operating noise. Most of the current literature research focuses on the measurement of the operating noise of offshore wind turbines, and based on the measurement results and related wind turbine parameters which design power, wind speed, distance and other parameters of the offshore wind turbine to derive the formula for offshore wind turbine operational noise. However, there are some hesitation about this method. Since offshore wind turbines currently contain a variety of different types of foundation, fixed foundations are divided into monopile, jacket, tripods and gravity types, while floating wind turbines are divided into tension leg, semi-submersible and spar, and these types have corresponding different parameters, these parameters will also affect the size of the operating noise, only the rated power of the wind turbine has the greatest impact. Therefore, this study will be based on the current way of assessing the piling noise of offshore wind turbines in Taiwan, follow a set of sound sources to simulate by the finite element method, and use the parabolic sound transmission equation to calculate the noise level of the operating noise of the offshore wind turbine transmitted to far field. This simulation method is currently widely used in piling noise assessment of offshore wind turbines. This study will be divided into three main parts, noise impact, simulation analysis and offshore floating wind turbine simulation. The noise impact section will review the noise related to offshore wind turbines, and then aim for the noise characteristics of the operating noise. In the end, it will focus on the impact of the noise on marine environment. The simulation analysis will be divided into three stages which to verify the input force function, the comparison of the actual case of the fixed foundation and the comparison of actual case of the offshore floating wind turbine. This study will use these three stage to verify the feasibility and accuracy of the method. In this study can solve the doubts about the prediction method of statistical regression from measured cases , and provide us with a basis for evaluating the impact of operating noise of offshore wind turbines in the future. Although this study can predict and simulate the operating noise of offshore wind turbines, there are also related situations that cannot be handled. This method is time-consuming and costly when dealing with the impact of multiple wind turbines. When corresponding to the above situation, the simulation results can be used for ANOVA analysis and regression analysis, and the operating noise formula of offshore wind turbines applicable to specific environments can be regressed. Nevertheless, the regression results in this study have certain limitations. If the sediment environment and parameters are out of range, the simulation and statistical analysis must be re-run. In addition, the design power of the case wind turbines used in this study is below 6MW, and additional verification is still required when dealing with high-power offshore wind turbines in the future.