本文選題：粒子圖像測(cè)速 + 直接數(shù)值模擬　； 參考：《水科學(xué)進(jìn)展》2017年05期

【摘要】：現(xiàn)今二維粒子圖像測(cè)速(PIV)廣泛應(yīng)用,為進(jìn)一步提高PIV測(cè)量結(jié)果對(duì)紊流及水流和泥沙相互作用機(jī)理的理解,分析了二維PIV中三維渦旋的可測(cè)性。結(jié)合渦旋識(shí)別的旋轉(zhuǎn)強(qiáng)度方法、坐標(biāo)旋轉(zhuǎn)定理和紊流經(jīng)典Burgers渦模型,推導(dǎo)得出:二維PIV能否檢測(cè)出三維渦旋,主要受渦旋環(huán)量和旋渦與測(cè)量平面之間的傾角兩個(gè)因素影響,且僅當(dāng)渦旋環(huán)量大于某一特定值(為傾角的函數(shù))時(shí),三維渦旋才可以被測(cè)量出。利用廣泛使用的直接數(shù)值模擬(DNS)槽道紊流數(shù)據(jù)統(tǒng)計(jì)分析,得出了該條件下傾角和環(huán)量的相關(guān)曲線與擬合方程;結(jié)合環(huán)量概率密度累積分布可知,在常規(guī)二維PIV實(shí)驗(yàn)中,渦旋被測(cè)量出的概率越大,相應(yīng)的傾角也越大,其中以90%、50%和10%的概率被測(cè)量出的三維渦旋與測(cè)量平面間分別呈20°、11°和5°的傾角。
[Abstract]:Nowadays, two-dimensional particle image velocimetry (PIV) is widely used. In order to further improve the understanding of turbulence and the interaction mechanism of flow and sediment in PIV measurements, the measurability of three-dimensional vortices in two-dimensional PIV is analyzed.Combined with the rotation intensity method of vortex recognition, coordinate rotation theorem and turbulent classical Burgers vortex model, it is deduced that whether two-dimensional PIV can detect three-dimensional vortex is mainly affected by vortex loop quantity and inclination angle between vortex and measuring plane.The three-dimensional vortex can only be measured if the vortex loop is greater than a certain value (a function of inclination angle).The correlation curves and fitting equations of dip angle and ring volume under this condition are obtained by using the widely used direct numerical simulation of the channel turbulence data statistical analysis, and combined with the cumulative distribution of the probability density of the ring volume, it is known that in the conventional two-dimensional PIV experiment,The larger the probability of vortex is, the greater the angle of inclination is. The angle between the measured 3D vortex and the measured plane is 20 擄11 擄and 5 擄, respectively, with the probability of 90% and 10%.
【作者單位】： 南京水利科學(xué)研究院水文水資源與水利工程科學(xué)國家重點(diǎn)實(shí)驗(yàn)室;
【基金】：國家自然科學(xué)基金資助項(xiàng)目(51609146) 南京水利科學(xué)研究院青年基金資助項(xiàng)目(Y216008)~~
【分類號(hào)】：TV149
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本文編號(hào)：1743588