渦尾流 的英文怎麼說
中文拼音 [guōwěiliú]
渦尾流
英文
vortex trail-
Boeing wants to use existing wing and tail control surfaces that shift up and down about 20 degrees in a coordinated fashion to disrupt the vortical flow
波音公司則利用現成的機翼與機尾控制面,讓它們互相協調、上下移動20度,以擾亂渦流。With the computing program, flow around the square cylinder is resolved at first, and the period of laminar flow is simulated successfully. during the period of vortex street ( re = 100 ), the periodically evolutionary phenomena of the flow behind the square cylinder can be seen
利用計算程序,本文首先對方柱繞流流動進行求解,成功模擬了方柱繞流層流階段的流動和渦街階段( re = 100 )方柱尾流的周期性變化現象。Because wake vortices can persist in calm air for several minutes ( extending for as far as eight miles ), the federal aviation administration requires minimum distances between aircraft, based on size
機尾渦流可以在無風的空氣中停留幾分鐘,向後延伸達12公里,所以美國聯邦航空總署按照飛機大小而規定了飛機之間的最小安全距離。The vortex simulated in this article include the shedding vortex induced by the vane trailing edge boundary layer, the endwall vortex generated by the endwall boundary layer interaction, the passage vortex generated by the rotor rotation, and the leakage vortex generated by the tip clearance flow
渦輪級內的渦運動包括:導向器葉片尾緣附而層引起的脫落渦;轉子通道內轉子的旋轉運動產生的通道渦;根腳區兩個端壁附面層干涉,形成的根腳渦;存在葉尖漏流時,出現的漏流渦。Based on an engineering background, through numerical simulation of the flow field in the hp turbine of the energy efficient engine ( e3 ), the article research the unsteady flow in a transonic turbine stage, the unsteady phenomena in the stage include the shockwave, wake, shedding vortex, endwall vortex, passage vortex and leakage vortex, etc. there are two shockwaves generated on the vane the tailing edge, one on suction side is named moving shockwave, and name another on pressure side steady shockwave
本文首先對于研究的意義和國內外研究的現狀做了簡要的介紹,再從某工程背景出發,通過對e3發動機高壓渦輪內流場的數值模擬,研究了干涉的周期性的問題,以及渦輪級內常見的非定常現象:激波、尾跡、脫落渦、根腳渦、通道渦、漏流渦。導向器尾緣會出現兩道激波,在吸力面的激波可稱為「運動」激波,壓力面的激波可稱為「定常」激波。In this paper, some characteristics of flow movement and sediment transport are analyzed by using the flume experiment data. the cross section of compound channel can be divided into four regions : the undisturbed region in main channel, the interactive region between channel and plain, the undisturbed region in flood plain and the boundary region. in the undisturbed regions, the distribution of longitudinal velocity along the depth has the feature of lograithmic. whereas, in the interactive region, the longitudinal velocity does not obey the logarithmic distribution law, but it can expressed as a revised logarithmic function by using a wake function. on the basis of the kinematic equation the velocity distribution of transverse velocity is obtained. in the boundary region, the longitudinal velocity obeys the law of parabolic distribution. furthermore, according to the simplified diffusion equation, the transverse distribution of sediment concentration in the interactive region is deduced. the analysis is in good agreement with the measured data
本文根據漫灘水流的運動特點,將漫灘水流的復式斷面分為主槽平衡區、灘槽交互區、灘地平衡區及邊壁區等4個區,並給出了各區寬度的經驗公式.根據灘槽交互區垂線流速分佈的變化特點,提出了附加尾流函數的對數流速分佈公式.在簡化水流運動方程和泥沙擴散方程的基礎上,對灘槽交互區內垂線平均流速及含沙量沿橫向分佈進行了理論分析,提出了反映灘槽水流動量交換強度的橫向渦量粘性系數及橫向擴散系數的表達式,得到了漫灘水流垂線平均流速及含沙量沿橫向分佈的解析解,並與實測資料吻合較好Based on the green ' s formula and the assumption of the propeller blade ' s thin sections, a lifting - surface method of propellers with the vortex lattice and equal source panel distributions on the mean camber surface has been introduced for the prediction of steady propeller ' s hydrodynamics in this paper. an approximate kurta condition was applied
基於creen公式和薄翼理論假設導出的升力面方法,採用在螺旋槳拱弧面上分佈離散渦、源布置方法預報均勻流場中的螺旋槳的定常性能,螺旋槳尾渦面上壓力連續性條件採用近似的kutta條件處理。The results indicated that the generation of trailing - vortex of downstream adjacent vanes could be restrained effectively by upstream wake when the passing frequency and the amplitude of wake defect satisfy some conditions, associated with a significant enhancement of time - averaged aerodynamic performances : loss coefficient reducing 40. 2 % and the ratio of loading coefficient and loss coefficient increasing 93 %
研究表明:滿足一定通過頻率和虧損幅值條件的尾跡能夠有效抑制下游相鄰葉排尾緣渦的生成,達到控制或是推遲附面層非定常分離的目的,從而使得流場時均性能大幅度的提高,損失系數降低了40 . 2 % ,功損比增加93 % 。Numerical simulation of unsteady vortex in the wake of cascade flow
葉柵流場尾跡中非定常渦系的數值模擬In light of the limitation of fast fourier transform ( fft ) for the method of traditional spectrum analysis to analyze the unsteady signal, wavelet and wavelet analysis are made for the typical unsteady process signal of starting up and shut down with the good characteristic of simultaneous localization in both the time and the frequency domains based on the field test on the vibration of two - row placed units in lijiaxia hydropower station, in which the signal is decomposed into different frequency band, and then the weak signal is caught and the dominant frequency is picked up for the analysis of the vibration source
摘要基於李家峽水電站雙排機組振動的現場試驗研究,並且針對傳統頻譜分析方法傅立葉變換( fft )對于非平穩信號已力不從心這一缺陷,利用小波分析方法在時域和頻域上同時具有良好的局部化性質,通過對開停機這一典型非平穩過程信號進行小波及小波包分析,將其分解到不同頻帶內,獲取微弱信息和提取優勢頻率,並對其作振源分析,得出開停機初始時刻因水流不穩均出現強烈的振動現象,且低頻段信號能量最大,開停機過程水流脈動壓力和尾水渦帶擺動是引起定子基礎振動的主要原因。One does this by redistributing the aerodynamic load along the wingspan or by incorporating the vortices coming off the horizontal stabilizer
為了造成這種結果,一個辦法是沿著翼展重新分配空氣動力負載,或是設法利用機尾水平穩定翼所產生的渦流。In arbitrary curvilinear coordinate systems, three dimensional turbulent combustion flow fields of the three kinds of turbofan engine afterburner with the longitudinal heat shield 、 outer cold flow and the jet nozzle are simulated. the three - dimensional body - fitted grids are generated by an elliptical grid generation procedure and zone method
本文在任意曲線坐標系統下對三種帶有縱向隔熱屏、外冷卻通道和尾噴管的渦扇發動機加力燃燒室的三維紊流燃燒流場進行數值模擬。Eventually mode a and b coexist in the wake, which confirms the previous studies. besides, the present paper finds that downstream the streamwise
從圓柱表面到旋渦形成區、到近尾跡再到下游尾跡流向渦結構從模式a轉換到模式b 、雙渦對模式、再恢復為模式a 。Wake vortex separation standards are used to prevent hazardous wake vortex encounters which mainly found in the final approach course within the airport termination zone. firstly, this paper analysis the mechanism of the vortex decay and research the influence on the safety of the flight ; then. several different radar wake vortex separation standards are compared and some basic guidelines are developed to establish the future vortex standards. in addition, one kind of advance vortex classification for the civil airplane is proposed. secondly, an encounter hazard model which established for the following aircraft and a simple vortex decay model which mostly concern with the proceeding one are developed ; and a safe separation model can be derived from the both. finally, through the simulation calculation, the correctness of the vortex classification of different types of aircrafts are tested and proved
本課題對雷達管制條件下的最小尾流間隔標準進行了較為詳細的分析和研究;首先對尾流的形成和消散機理以及尾流對飛行安全的影響做出了詳細的分析,然後就目前實行的幾種不同的最小尾流間隔標準進行了比較和分析,提出了相關的幾條準則和一種改進的機型尾流分類標準;在這之後,採用理論分析和統計數據分析相結合的方法,建立了尾流危險遭遇基本模型和尾渦消散模型;並在此基礎上對民用航空不同機型的尾流分類的合理性進行了計算和評估,為最小尾流間隔標準的確定和改進提供了初步的理論依據。Large eddy simulation of gas - particle two phase turbulence was carried out, such as simulation of two - dimensional gas - particle two phase wake, two - dimensional gas - particle two phase jet and three - dimensional gas - particle two phase rectangular jet. in these works, les was adopted to simulate gas phase flow and lagrangian approach was utilized to simulate the particles " motion. a series of significant and interesting results were obtained
文中對二維氣粒兩相平面尾跡流場、二維氣粒兩相平面射流流場以及三維氣粒兩相矩形射流流場中的氣相流場進行了大渦模擬、對顆粒運動擴散採用lagrangian模擬研究后,取得了一系列具有重要的理論意義和實際意義的研究成果。The vortex - excited oscillation, wake galloping, rain - wind vibration and buffetting are the main cause of the fatigue in the vicinity of the anchorages on cables of cable stayed bridges
渦激振、風雨振、尾流馳振、抖振等風致振動容易造成斜拉橋拉索錨固端疲勞,促使銹蝕加快,嚴重影響拉索的使用壽命。Stay cable, which is one of the important components in cable - stayed bridges, is susceptible to environmental excitation because of its small weight, large flexible, low damping, then the various vibration is induced, such as vortex - induced vibration, wake galloping, rain vibration, buffeting as well as parametric - induced vibration etc. in this paper, the vibration property of stay cable has firstly been introduced
斜拉索是斜拉橋的重要承力構件,由於拉索自身的質量輕、柔度大、阻尼小,在外界激勵下,易發生各種振動,包括渦激振、尾流馳振、風雨振、抖振以及參數振動等。Stay cables of the long - span cable - stayed bridges are susceptible to vibration under wind loading, or wind incorporated rain excitation, or deck motion due to high flexibility, relatively small mass and very low inherent damping, such as vortex shedding, wake galloping, parameter resonance and wind - rain induced vibration. large - amplitude vibration of cables may reduce the life of cables and threaten safe traffic, and has been considered today as one of the most critical problems for this type of bridge
大跨度斜拉橋拉索具有較小的質量和極低的阻尼,在風、風雨及橋面振動等外部激勵下極易發生振動,如渦激共振、尾流馳振、參數共振和風雨振等,拉索的大幅振動對拉索的使用壽命和橋梁安全運營構成極大威脅,它已成為大跨度斜拉橋急需解決的關鍵問題之一。The complex vortex system structure and shock wave system structure inside this rotor is obtained. wall flow patterns on the blade surface and hub surface are found out. the complex vortex system structure, such as horseshoe vortex, passage vortex, corner vortex and trailing vortex, and the interaction with shock wave system are researched. especially, the character of the tip clearance flow inside the rotor passage is revealed, and the interaction between shock wave and tip clearance flow near blade tip and the evolution of tip clearance flow are considered
給出了葉片表面及輪轂面上的壁面流型,分析並揭示了轉子葉道內的馬蹄渦、通道渦、角渦、尾渦等復雜渦系及其與激波的相互干涉;特別是,分析並揭示了轉子葉道內頂隙射流的特點,得到了頂隙附近激波與泄漏流動的干涉形態及泄漏流動的發展,並著重給出了其與激波的干涉形態。An experimental study on the vortex - induced vibrations of a circular cylinder was conducted to investigate the vibration of the towed - cable when the towed array sonar was dragged underwater
摘要為了考察圓柱型聲納陣拖纜在水下拖曳時,由於尾流中發放旋渦激起的渦激振動情況和有關規律,進行了試驗研究。分享友人