Of course overlap grid also has its shortcoming : in the application of this method , the pre - disposal process of computational grid to find the interpolating connection , so - called “ dig - hole ” process , is hardly to proceed automatically 多年來,重疊網(wǎng)格的應(yīng)用基本上是根據(jù)一套繁瑣的處理方法,針對具體外形編寫具體程序的處理過程來實(shí)現(xiàn),成為長期以來制約重疊網(wǎng)格應(yīng)用的瓶頸。
This method has different consideration with conventional ways , it can reduce the disposal time for almost 100 times , and resolve the efficiency problem successfully . with the help of research in this paper , the capability of using overlap grid has been improved greatly and many old work based on structural - grid , such as difference scheme , turbulence model , can be used in moving - grid field of overlap grid technology and expand our research field for cfd remarkably 通過本文的研究,使我們應(yīng)用重疊網(wǎng)格處理復(fù)雜外形的能力得到顯著提升并使我們基于結(jié)構(gòu)網(wǎng)格做的許多研究工作,如各種差分格式以及各種湍流模型的比較研究、大攻角問題等專項(xiàng)研究平滑地過渡到基于重疊網(wǎng)格的動網(wǎng)格應(yīng)用領(lǐng)域來,較大地拓展了我們的研究應(yīng)用領(lǐng)域。
The conventional ways has low efficiency , which result in the application of overlap grid in moving - grid problem , which need re - disposes the interpolating connection in every step in time direction , is very difficult considering the computational efficiency . aim at the above problem in application of overlap grid , this paper using an new manner rooting in analysissitus to put forward a “ method of distinguishing points of intersection ” and develop corresponding computational soft , which could realize the automatic and shape - independent pre - disposal process for overlap grid . to deal with the problem of low efficiency for pre - disposal process in moving - grid , this paper bring forward the “ mosaic ” method and adt method which based on the huge memory of modern computer 對于重疊網(wǎng)格在動網(wǎng)格應(yīng)用中的計(jì)算效率問題,本文通過進(jìn)一步研究插值信息的高速查詢方法,提出不同于傳統(tǒng)算法思路,以現(xiàn)代計(jì)算機(jī)大內(nèi)存為基礎(chǔ),用計(jì)算機(jī)物理內(nèi)存空間換計(jì)算時(shí)間的” mosaic ”方法以及應(yīng)用基于二叉樹數(shù)據(jù)結(jié)構(gòu)的adt ( alternatingdigitaltree )方法兩類方法,成功的將原處理時(shí)間提高了兩個(gè)數(shù)量級? ?即將網(wǎng)格規(guī)模在百萬量級的重疊網(wǎng)格預(yù)處理時(shí)間從傳統(tǒng)方法的耗時(shí)30 60分鐘提高到幾十秒鐘,從而成功解決了這一問題。
For a long time , user must complete this step with a series of complex methods by hand , and this problem became the choke point in application and development of overlap grid technology . in the moving - grid problem with fluctuant shape , the pre - disposal process of overlap grid is a main difficulty 對于重疊網(wǎng)格對復(fù)雜外形適應(yīng)能力問題,本文借用拓?fù)鋵W(xué)中關(guān)于幾何外形拓?fù)潢P(guān)系的新思路,即射線判別法,發(fā)展出”重疊網(wǎng)格交點(diǎn)判別法”并編寫相應(yīng)軟件,實(shí)現(xiàn)了與幾何外形無關(guān)、無須人工干預(yù)的通用、自動化重疊網(wǎng)格預(yù)處理。
Grid generation is a pivotal technology of cfd ( computational fluid dynamics ) . follow the complication of problem in cfd field , the grid generation technology has developed in two ways : in the first place , it improved grid generation method to adopt the increasingly complicated figuration ; on the other hand , it developed new methods to deal with the problem including fluctuant surface , such as multi - body separation problem etc . among this ways , the overlap grid technology is a vive research aspect 網(wǎng)格技術(shù)是cfd ( computationalfluiddynamics )領(lǐng)域中的關(guān)鍵技術(shù)。隨著cfd涉及問題的復(fù)雜化,網(wǎng)格技術(shù)在兩個(gè)方向上逐步發(fā)展:一方面針對不斷復(fù)雜的外形處理需求改進(jìn)網(wǎng)格方法,從而能夠模擬復(fù)雜飛行器及其各個(gè)氣動部件的細(xì)節(jié);另一方面發(fā)展適應(yīng)撲翼、多體分離等變幾何外形問題的網(wǎng)格方法,使得cfd的工程應(yīng)用領(lǐng)域不斷拓寬。這其中,重疊網(wǎng)格方法是一個(gè)較有活力的研究方向。