本文關(guān)鍵詞： 潛冰啟動(dòng) 物理模型 數(shù)值模型 臨界條件 壓差分布　出處：《天津大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：高緯度地區(qū)的輸水渠道在冬季輸水過(guò)程中，會(huì)形成冰塞、冰壩等冰情現(xiàn)象。這將顯著的減小輸水流量、抬高水位，而冰塞體的潰決會(huì)造成下游更嚴(yán)重的災(zāi)害。下潛至冰蓋底面的冰凌稱為潛冰。由于冰凌下潛和停滯是冰塞形成和發(fā)展的基礎(chǔ)，在研究冰凌下潛臨界條件的基礎(chǔ)上，本文進(jìn)一步研究潛冰運(yùn)動(dòng)規(guī)律，，特別是停滯與啟動(dòng)的臨界條件，對(duì)冰害的防治具有重要意義。 本文采用物理模型與數(shù)值模擬相結(jié)合的方法進(jìn)行研究，按照重力相似準(zhǔn)則，開(kāi)展了不同水流條件和冰凌尺度的潛冰運(yùn)動(dòng)物理模型試驗(yàn)；建立了三維數(shù)值模型，分析潛冰的水動(dòng)力特性，并獲得了潛冰停滯與啟動(dòng)臨界條件。具體研究?jī)?nèi)容與成果概括如下： （1）選擇密度接近天然冰密度的聚乙烯作為冰蓋和潛冰的模型材料。對(duì)模型試驗(yàn)的相似準(zhǔn)則進(jìn)行了研究，按照重力相似準(zhǔn)則對(duì)潛冰的運(yùn)動(dòng)狀態(tài)進(jìn)行了物理模型試驗(yàn)。通過(guò)改變冰蓋下水流速度V、水深h及潛冰的形狀（厚度t，長(zhǎng)度l，寬度b）等因素，證實(shí)了潛冰的縱向啟動(dòng)流速大于橫向啟動(dòng)流速。潛冰運(yùn)動(dòng)規(guī)律研究的關(guān)鍵為研究縱向狀態(tài)潛冰的臨界條件——停滯與啟動(dòng)。試驗(yàn)獲得了潛冰臨界狀態(tài)的影響因素：隨著相對(duì)形狀t/l，相對(duì)水深t/h及相對(duì)寬度b/B的增加，潛冰的臨界冰厚Froude數(shù)Ft相應(yīng)減小。對(duì)不同工況下試驗(yàn)數(shù)據(jù)進(jìn)行回歸分析，得到更為準(zhǔn)確的潛冰滑動(dòng)啟動(dòng)臨界條件的形式。 （2）為進(jìn)一步分析潛冰的臨界狀態(tài)，采用數(shù)值模擬研究潛冰底面水壓力的計(jì)算方法。結(jié)合Realizable-紊流模型，及壁面函數(shù)對(duì)潛冰底面的文丘里效應(yīng)和前緣效應(yīng)進(jìn)行了精準(zhǔn)的模擬。以Larsen的物理模型試驗(yàn)為原型建立數(shù)值模型，獲得冰蓋下流速V沿水深h的分布情況。將數(shù)值模型輸出結(jié)果與試驗(yàn)數(shù)據(jù)進(jìn)行對(duì)比，證實(shí)模擬結(jié)果的有效性。通過(guò)分析文丘里效應(yīng)和前緣效應(yīng)的影響因素：冰蓋下水流流速V，相對(duì)水深t/h和相對(duì)寬度b/B，得到了非全寬潛冰的文丘里效應(yīng)和前緣效應(yīng)的修正計(jì)算公式。在此基礎(chǔ)上進(jìn)行積分，獲得了潛冰底面水壓力的估算公式。 （3）基于對(duì)水壓力、拖曳力、剪切力、有效浮力及摩擦力的研究，分析潛冰的受力平衡，獲得了潛冰停滯與啟動(dòng)臨界條件的計(jì)算公式。通過(guò)對(duì)比該計(jì)算公式與試驗(yàn)數(shù)據(jù)，驗(yàn)證了計(jì)算公式的準(zhǔn)確性。
[Abstract]:In the course of winter water conveyance in high latitudes, ice jams, ice dams and other ice conditions will be formed. This will significantly reduce the flow of water and raise the water level. And the collapse of the ice plug can cause a more serious disaster downstream. The ice that submerges to the bottom of the ice sheet is called ice diving. Because the ice drop and stagnation are the basis for the formation and development of the ice slug, on the basis of studying the critical conditions for ice ice diving, In this paper, it is of great significance to study the law of submersible ice movement, especially the critical condition of stagnation and start-up, for the prevention and cure of ice damage. In this paper, the method of combining physical model with numerical simulation is used to study, according to the principle of gravity similarity, the physical model tests of subsurface ice motion with different flow conditions and ice scale are carried out, and the three-dimensional numerical model is established. The hydrodynamic characteristics of submersible ice are analyzed, and the critical conditions of ice stagnation and start-up are obtained. The specific research contents and results are summarized as follows:. 1) Polyethylene with density close to natural ice density was selected as model material for ice sheet and latent ice. The similarity criterion of model test was studied. According to the gravity similarity criterion, the physical model tests on the motion state of submerged ice have been carried out. By changing the velocity of flow under the ice cap, water depth h and the shape (thickness t, length l, width b) of the submerged ice, and so on, some factors, such as thickness t, length l, width b, are changed. It is proved that the longitudinal start-up velocity is higher than the transverse starting velocity. The key to the study of the law of submersible ice motion is to study the critical condition of the longitudinal state of submerged ice-stagnation and startup. The factors affecting the critical state of submersible ice are obtained by experiments. With the relative shape of t / L, the relative depth of water t / h and the relative width of b / r / B, The critical ice thickness Froude number (Ft) of submersible ice decreases correspondingly. Regression analysis is carried out on the test data under different operating conditions to obtain a more accurate form of critical conditions for submersible ice sliding starting. (2) in order to further analyze the critical state of submerged ice, a numerical simulation method is used to study the water pressure at the bottom of the submerged ice. The Venturi effect and the leading edge effect on the underlying surface of the submerged ice are simulated accurately with the wall function. The numerical model is established based on Larsen's physical model test. The distribution of velocity V along the water depth h under the ice cap is obtained. The numerical model output results are compared with the experimental data. By analyzing the influencing factors of Venturi effect and leading edge effect, such as velocity of flow under ice cap, relative depth t / h and relative width b / B, the Venturi effect and leading edge effect of incomplete wide diving ice are obtained. Revise the calculation formula. On this basis, the integral, A formula for estimating the water pressure at the bottom of subsurface ice is obtained. Based on the study of water pressure, towing force, shear force, effective buoyancy force and friction force, the stress balance of submersible ice is analyzed, and the formula for calculating the critical condition of stagnation and start-up of submersible ice is obtained. The accuracy of the formula is verified.
【學(xué)位授予單位】：天津大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2014
【分類號(hào)】：TV672;TV133

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 徐和龍,董繼英;冰期對(duì)引黃濟(jì)津輸水的影響[J];海河水利;2001年S1期

2 張成;王開(kāi);;冰期輸水研究進(jìn)展[J];南水北調(diào)與水利科技;2006年06期

3 李根生;王建新;牟純?nèi)?許玉生;邊自然;;引黃濟(jì)津冬季輸水冰情觀測(cè)與分析[J];南水北調(diào)與水利科技;2006年S1期

4 任光林;;冰期過(guò)流量計(jì)算與冰面曲線推求[J];海河水利;1984年02期

5 趙新;練繼建;黃焱;;基于真冰模型試驗(yàn)的冰蓋穩(wěn)定性研究[J];水利水電技術(shù);2011年10期

6 王軍;付輝;伊明昆;尹運(yùn)基;高月霞;;冰塞水位分析[J];水科學(xué)進(jìn)展;2007年01期

7 李志軍;孫萬(wàn)光;許士國(guó);李青山;白炎;王昕;;短期水文氣象資料估算哈爾濱至同江冰厚度[J];水科學(xué)進(jìn)展;2009年03期

8 王軍,孫連進(jìn);冰蓋下散粒體泥沙起動(dòng)流速的試驗(yàn)研究[J];水利水運(yùn)科學(xué)研究;1998年02期

9 王軍,孫連進(jìn),周智慧;冰塞下冰塊起動(dòng)分析[J];水利水運(yùn)科學(xué)研究;1999年02期

10 茅澤育,趙升偉,相鵬,岳光溪;冰蓋下水流流動(dòng)的摻混特性[J];水利學(xué)報(bào);2005年03期

本文編號(hào)：1507633