The explicit method is widely used for its simpleness and little memory consumed with local time step and variable coefficients implicit residual smooth to accelerate the convergence procedure . according to yoon and jameson ' s ideas , an efficient implicit lu - sgs algorithm is carefully constructed by combing the advantages of lu factorization and symmetric - gauss - seidel technique in such a way to make use the l and u operators scalar diagonal matrices , thus the numeric algorithm requires only scalar inversion . the computational efficiency is greatly improved with this scheme 顯式方法具有簡單,消耗內(nèi)存小等優(yōu)點,并采用當(dāng)?shù)貢r間步長、變系數(shù)隱式殘值光順等加速收斂措施,在定常流動的模擬中得到了廣泛的應(yīng)用;根據(jù)yoon和jameson提出的簡化正、負矩陣分裂,構(gòu)造的l 、 u算子只需進行標量對角陣求逆,極大提高了流場數(shù)值求解過程的計算效率;采用newton類型的偽時間子迭代技術(shù)使時間推進精度提高至二階。
Recently , changes have taken place in the field of english teaching , especially on the methods of teaching grammar in the china ' s middle schools : implicit methods of learning grammar rules are replacing explicit methods , class activities are beginning to focus on developing students " communication skills rather than grammar rules 近幾年來,我國外語教學(xué)領(lǐng)域發(fā)生了很大變化,尤其是中學(xué)外語教學(xué)對語法教學(xué)進行了重大改革:一改過去用直接法講解理論知識,而采用含蓄法培養(yǎng)學(xué)生的交際能力,讓他們在實際應(yīng)用中掌握英語語法規(guī)律。
The theoretic calculating method of the maximum and the minimum water level in the differential surge tank has been derived firstly . also the explicit method of calculating surges in the differential surge tank has been deduced firstly by use of thaler series expansion . the calculating method of section of the well and the effective impedance hole in the surge tank has been gived 根據(jù)差動式調(diào)壓室的基本微分方程,首次推導(dǎo)出了差動式調(diào)壓室涌浪幅值的理論計算公式;并同樣利用泰勒級數(shù)展開方法推導(dǎo)出了差動式調(diào)壓室水位波動的顯式計算式;導(dǎo)出了差動式調(diào)壓室大井面積和有效阻抗孔面積的計算方法。