船舶力学
船舶力學
선박역학
JOURNAL OF SHIP MECHANICS
2009年
3期
477-489
,共13页
刘彦森%盛美萍%陶红丹%肖和亚
劉彥森%盛美萍%陶紅丹%肖和亞
류언삼%성미평%도홍단%초화아
水下扁平结构%散射声场%边界元法%附加边缘结构%边缘结构附加方式
水下扁平結構%散射聲場%邊界元法%附加邊緣結構%邊緣結構附加方式
수하편평결구%산사성장%변계원법%부가변연결구%변연결구부가방식
underwater flat structure%scattered acoustic field%Boundary Element Method%appended edge structure%appended mode of edge structureFouondation item: Supported by the New Century Talent Program of Ministry of Education (Grant No. NCET-04-0959)and the Spe
鉴于实际中存在的水下扁平结构的边缘特点,也为研究不同边缘附加结构形式对其散射声场的影响规律,并为边缘衍射效应影响抑制机理与技术等奠定基础,本文通过采用边界积分方法和边界元数值计算技术,并结合水下目标散射强度估计和水声无源材料自由场测试等工程实际,对不同边缘结构形式的水下扁平结构在不同频率范围和空间几何配置条件下的散射声场分布规律开展了定量的研究与分析.研究结果表明:在发射声源与结构几何配置等条件一定的情况下,无论前向散射还是镜向散射,附加边缘结构扁平矩板结构散射声场在频域和空间分布趋势上与未附加边缘结构的基本一致,即低频段起伏较小,而中高频段则波动较为剧烈,与结构距离越近越剧烈,这在前向散射中表现得尤为明显,其与波贡献主要成分、附加边缘的结构类型、边缘结构附加方式、结构参数、声波相干作用和边缘重数等因素密切相关.
鑒于實際中存在的水下扁平結構的邊緣特點,也為研究不同邊緣附加結構形式對其散射聲場的影響規律,併為邊緣衍射效應影響抑製機理與技術等奠定基礎,本文通過採用邊界積分方法和邊界元數值計算技術,併結閤水下目標散射彊度估計和水聲無源材料自由場測試等工程實際,對不同邊緣結構形式的水下扁平結構在不同頻率範圍和空間幾何配置條件下的散射聲場分佈規律開展瞭定量的研究與分析.研究結果錶明:在髮射聲源與結構幾何配置等條件一定的情況下,無論前嚮散射還是鏡嚮散射,附加邊緣結構扁平矩闆結構散射聲場在頻域和空間分佈趨勢上與未附加邊緣結構的基本一緻,即低頻段起伏較小,而中高頻段則波動較為劇烈,與結構距離越近越劇烈,這在前嚮散射中錶現得尤為明顯,其與波貢獻主要成分、附加邊緣的結構類型、邊緣結構附加方式、結構參數、聲波相榦作用和邊緣重數等因素密切相關.
감우실제중존재적수하편평결구적변연특점,야위연구불동변연부가결구형식대기산사성장적영향규률,병위변연연사효응영향억제궤리여기술등전정기출,본문통과채용변계적분방법화변계원수치계산기술,병결합수하목표산사강도고계화수성무원재료자유장측시등공정실제,대불동변연결구형식적수하편평결구재불동빈솔범위화공간궤하배치조건하적산사성장분포규률개전료정량적연구여분석.연구결과표명:재발사성원여결구궤하배치등조건일정적정황하,무론전향산사환시경향산사,부가변연결구편평구판결구산사성장재빈역화공간분포추세상여미부가변연결구적기본일치,즉저빈단기복교소,이중고빈단칙파동교위극렬,여결구거리월근월극렬,저재전향산사중표현득우위명현,기여파공헌주요성분、부가변연적결구류형、변연결구부가방식、결구삼수、성파상간작용화변연중수등인소밀절상관.
Due to the fact that a certain edge shape is always appended to the underwater fiat struc-tures, in order to investigate the influence of different typical edge shapes on the scattering field, and lay a foundation for the research of suppressing technique of the edge -diffracted effect, the Boundary Integral Method (BIM) and the Boundary Element Method (BEM), combined with the underwater tar-get strength estimation and the measurement for underwater acoustical passive material in the free field,are applied to study and analyze the characteristic of scattering field distribution quantitatively in different frequency ranges and spatial geometrical configurations for underwater flat structures with different edge shapes.The results show that when the geometrical configuration of the emitting sound source and the structure are unchanged, no matter the forward scattering or the mirror scattering, the distribution trend of scattering field of the flat rectangular structures with appended edge structure in frequency ranges and spatial distribution accords basically with the flat rectangular structures without appended edge structure. That is, the fluctuation is very slender in low frequency, while very acute in mid and high frequency; especially more acuter when the receiving point is in the neighborhood of the structure, which is more obvious in the forward scattering.And these are concerned with some fac-tors such as the main contribution part of the wave field,the shape of the appended edge structure,appended mode of edge structure, structural parameters, the coherence effect of acoustical wave, the number of edge layer, and so on.