本文選題：格子Boltzmann方法 + MRT-LBE　； 參考：《北方民族大學(xué)》2017年碩士論文

【摘要】：天然河道、水庫、湖泊中水生植被的存在,干擾了水流流場,從而對泥沙運移、河道演變、水庫淤積、水環(huán)境和水生態(tài)產(chǎn)生較大影響.本文利用三維激光多普勒測速儀(laser Doppler velometer,LDV)等儀器對實驗室水槽中含有不同排列方式的植被水流特性進行了實測與分析,并建立了多松弛格子Boltzmann方程(multi-relax time lattice Boltzmann equation,MRT-LBE),研究了其數(shù)值算法,并對含植被實驗室水槽水流問題進行了數(shù)值模擬研究.研究結(jié)果具有一定的理論意義和實際工程應(yīng)用價值,可為河道治理及水生態(tài)環(huán)境建設(shè)提供參考.具體內(nèi)容包括以下幾個方面:首先,綜述計算流體動力學(xué)的產(chǎn)生、發(fā)展歷程和與傳統(tǒng)數(shù)值模擬方法的對比.同時追溯格子Boltzmann方法(lattice Boltzmann Method,LBM)的由來、發(fā)展.系統(tǒng)地給出格子Boltzmann方法的離散速度模型、邊界處理方式,并利用經(jīng)典算例進行了驗證.其次,利用LDV對實驗室水槽中含不同直徑、不同排列方式的四種典型工況(稀疏交錯、稠密交錯、稀疏并排、稠密并排)在非淹沒剛性植被的水流結(jié)構(gòu)進行了實測.對實測數(shù)據(jù)利用Matlab等有關(guān)軟件進行處理,分析了水流經(jīng)過植被群前后,水面雍高、流速變化、水面坡降、水力坡降等情況.通過比較分析,得到了四種典型工況下植被區(qū)的水流特性.最后,基于LBM對具有剛性植被的實驗室水槽水流進行了二維數(shù)值模擬研究.由于單松弛模型(SRT)在雷諾數(shù)較大時,會出現(xiàn)不穩(wěn)定現(xiàn)象,本文利用多松弛模型(MRT-LBE)進行數(shù)值模擬.根據(jù)實測結(jié)果與數(shù)值模擬結(jié)果的對比,在模型中加入了植被“拖曳力”,建立了適用于含植被水流數(shù)值模擬的MRT-LBE模型,并給出了具體算法.對四種典型工況下水流運動進行了數(shù)值模擬,并與實測結(jié)果進行了比較.模擬結(jié)果與實測數(shù)據(jù)相對吻合,表明所建立模型可用于明渠和河流中含植被水流運動.計算機數(shù)值模擬時,由于模擬區(qū)域的對稱性,只對其中一半?yún)^(qū)域進行模擬,水槽中心線處采用對稱性邊界條件進行處理.這樣不僅可節(jié)約計算量,也可以節(jié)約計算機內(nèi)存.對于固壁采用反彈邊界條件進行處理,進口邊界根據(jù)實測數(shù)據(jù)給出,出口邊界為充分發(fā)展邊界。
[Abstract]:The existence of aquatic vegetation in natural rivers, reservoirs and lakes interferes with the flow field, which has a great influence on sediment transport, river evolution, reservoir deposition, water environment and water ecology. This paper uses laser Doppler velometer (LDV) and other instruments for different arrangement of vegetation water in the laboratory water tank. The flow characteristics are measured and analyzed, and the multi relaxation lattice Boltzmann equation (multi-relax time lattice Boltzmann equation, MRT-LBE) is established, and its numerical algorithm is studied. The numerical simulation of the water flow problem in the water tank with vegetation laboratory is studied. The results have some theoretical significance and practical engineering application value. It provides reference for river management and water ecological environment construction. The specific contents include the following aspects: first, it summarizes the generation of computational fluid dynamics, the development process and the comparison with the traditional numerical simulation methods. At the same time, the origin of the lattice Boltzmann method (lattice Boltzmann Method, LBM) is traced, and the lattice Boltzmann method is systematically given. The discrete velocity model, the boundary treatment method and the classic example are verified. Secondly, the flow structure of the non submerged rigid vegetation is measured by four typical working conditions (sparse staggered, dense staggered, sparse side by side, dense side by side) in the laboratory water tank with different diameters and different arrangement modes in the laboratory water tank with LDV. Matlab and other related software are processed, and the water flow passes through the vegetation group, the water surface Yonggao, the flow velocity change, the water surface slope, the hydraulic slope and so on. Through the comparative analysis, the flow characteristics of the vegetation area under the four typical conditions are obtained. Finally, the two-dimensional numerical simulation of the water flow in the laboratory water tank with rigid vegetation is carried out based on the LBM. In this paper, the single relaxation model (SRT) will be unstable when the Reynolds number is large. In this paper, the multi relaxation model (MRT-LBE) is used to simulate the numerical simulation. According to the comparison between the measured results and the numerical simulation results, the "towing force" of the vegetation is added to the model, and a MRT-LBE model suitable for the numerical simulation of the vegetation flow is set up, and the results are given. The numerical simulation of flow motion under four typical operating conditions is carried out and compared with the measured results. The simulation results are in good agreement with the measured data, which shows that the established model can be used for the movement of the vegetation flow in the open channel and the river. In the simulation, the center line of the sink is treated with symmetric boundary conditions. This can not only save calculation and save computer memory, but also deal with the bounce boundary condition for the solid wall, and the import boundary is given according to the measured data, and the exit boundary is fully developed boundary.

【學(xué)位授予單位】：北方民族大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O35

【參考文獻】

相關(guān)期刊論文 前10條

1 吳龍華;楊校禮;;挺水植被狀態(tài)對水流阻力影響的實驗研究[J];水動力學(xué)研究與進展A輯;2015年04期

2 渠庚;張小峰;陳棟;陳靜婷;丁兵;;含柔性植物明渠水流阻力特性試驗研究[J];水利學(xué)報;2015年11期

3 張金鳳;常璐;馬平亞;;高雷諾數(shù)頂蓋驅(qū)動方腔流實驗[J];水科學(xué)進展;2015年02期

4 劉超;劉興年;楊克君;;Predictive model for stage-discharge curve in compound channels with vegetated floodplains[J];Applied Mathematics and Mechanics(English Edition);2014年12期

5 鐘強;陳啟剛;李丹勛;王興奎;;明渠湍流橫向渦旋的尺度與環(huán)量特征[J];四川大學(xué)學(xué)報(工程科學(xué)版);2013年S2期

6 丁磊;楊鑫;周程婷;劉偉;;植被剛度及其阻力特性研究可視化軟件開發(fā)[J];山西水利科技;2013年02期

7 槐文信;楊水草;楊中華;李丹;;基于水深平均模型的植被水流數(shù)值模擬[J];深圳大學(xué)學(xué)報(理工版);2012年01期

8 盧國范;姜俊龍;;圓柱繞流的格子Boltzmann模擬[J];遼寧工程技術(shù)大學(xué)學(xué)報(自然科學(xué)版);2010年03期

9 羅晶;楊具瑞;譚毅源;田振華;;濕地剛性植物對水流結(jié)構(gòu)影響的三維數(shù)值模擬[J];水電能源科學(xué);2010年01期

10 楊紀偉;鄭薇薇;李書芳;;串列雙圓柱水流特性試驗研究[J];南水北調(diào)與水利科技;2009年02期

相關(guān)碩士學(xué)位論文 前1條

1 程莉;植樹護岸條件下河道水流水流的數(shù)值模擬[D];河海大學(xué);2002年

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