Then, while local resistance of three-way pipe applying to hydraulic computation of the pipe network , draw : (1) Hydraulic computation in large-scale water supply pipe network ( l / d ≥1000) , some local loss comparing with head loss, Its value is relatively small, can be ignored in engineering calculation;

接着,把三通的局部阻力引进管网的水力计算中,得出:(1)在大型管网即l / d ≥1000以上的给水管网计算中,局部损失和水头损失相比,其值相对较小,在工程计算中可以忽略不计;

The efflux element solely serving as the study subject and on condition that the linear loss and the local loss are ignored, the paper applies the Berloulli equation to conclude the calculation result, which shows that the cavitation corrosion exists in the inside of the efflux element at certain discharge of pump in theory, and the theoretical analysis consists with the actual condition.

Furthermore, an improved genetic algorithm is introduced to optimize the roughness, the revised coefficient of energy or the synthesis coefficient of local loss, which makes the parameter more reasonable.

In the paper, the local loss coefficient at sudden expansion under the condition of three kinds of A\-1A\-2 is studied by experiment. In the end, the result shows that ξ\-1 is related not only to two flow cross sections, but also to the velocity.

Then, while local resistance of three-way pipe applying to hydraulic computation of the pipe network , draw : (1) Hydraulic computation in large-scale water supply pipe network ( l / d ≥1000) , some local loss comparing with head loss, Its value is relatively small, can be ignored in engineering calculation;

接着,把三通的局部阻力引进管网的水力计算中,得出:(1)在大型管网即l / d ≥1000以上的给水管网计算中,局部损失和水头损失相比,其值相对较小,在工程计算中可以忽略不计;

Pressure distributions along convex side of wall are more even and maximum pressure gradient on there appears later than along concave side of wall as the local loss coefficients for fronter are lower than later. Test data shows good agreement with calculating results discoverd subsequently.

3)It decreases the local resistant coefficient and the local loss of water head. 4)It improves the distribution of pressure on the runner. 5)It makes the flow more even in each multi-ingate with equal cross section.

Based on experimental analysis and theoretical discussion of local loss coefficient ξ in sudden enlargement circular pipe,a usable equation was suggested which had an additional correction coefficient.

In some practice, only it's ratio of double-end cross-sections and diffuser angle are considered, but the states of flow are ignored. In this aspeet, this article gives overall consideration and made special experiments at the pipeline with 5·7° diffuser angle and 0.25 cross-se(tior) ratio and measured local loss coefficienf of diffuser in different state of flow, that gives the basis for pipeline designing.

The phenomenon of the local loss of stability (buckling) earlier discovered by the authors experimentally was simulated theoretically.

Shells in the second group have ω>amp;gt;1, which characteristically manifest a local loss of stability.2.For shells with L≤2D, the critical loads PK are practically identical for single-sided and through holes.

The effect of occurrence of a local surface phase transformation is predicted, which is caused by a local loss of stability of the statistical distribution of atoms of components on the surface due to the presence of interstitial impurity atoms.

Results indicate that local loss measurements can be performed on fibre sections which are remote from the source by a distance corresponding to a fibre attenuation of 27 dB.

Stress redistribution in a composite material upon a local loss of plastic stability of the fibers

In order to disclose the effect of sprue—down—well,this article states a research on the pouring tests of two kinds of hydraulic models for comparision by means of hydraulic simulating method.One of them has sprue—down—well,but the other has none.It is found that there are some important effects occurred in a good sructural sprue—down—well.as following: 1)It produces a cttshioning effect at the bottom of the sprue. 2)It shortens the transition region of turbulization,Which occurs at the corners of the sprue—runner....

In order to disclose the effect of sprue—down—well,this article states a research on the pouring tests of two kinds of hydraulic models for comparision by means of hydraulic simulating method.One of them has sprue—down—well,but the other has none.It is found that there are some important effects occurred in a good sructural sprue—down—well.as following: 1)It produces a cttshioning effect at the bottom of the sprue. 2)It shortens the transition region of turbulization,Which occurs at the corners of the sprue—runner. 3)It decreases the local resistant coefficient and the local loss of water head. 4)It improves the distribution of pressure on the runner. 5)It makes the flow more even in each multi-ingate with equal cross section. This paper also gives a brief description of the view of some foreign researchers.We make some necessary analysis of the effect mechanism of sprue—down—Well.

The double sweeping method is a simple and effective for numerically solving Saint-Venant eqs. in implicit scheme. In natural rivers it is quite often that the conditions of concentritive lateral flow, pond connectted with main channles, local loss of water head, sluice etc. shoud be taken into consIderation, the double sweeping method easily solve these problems in computation by means of adding a computational reach.This additional reach should be the same as the normal reach. but its coefficients are...

The double sweeping method is a simple and effective for numerically solving Saint-Venant eqs. in implicit scheme. In natural rivers it is quite often that the conditions of concentritive lateral flow, pond connectted with main channles, local loss of water head, sluice etc. shoud be taken into consIderation, the double sweeping method easily solve these problems in computation by means of adding a computational reach.This additional reach should be the same as the normal reach. but its coefficients are determined by their special connection conditions.The double sweeping method also can be easily applied to compute the unsteady flow in networks of channels.

Two dimensional internal flow near a curved wall with positive pressure gradient is discussed in this paper based on boundary-layer theory. A technical approach for calculating development of turbulent boundary-layer is presented and its test data are also given. Theoretical calculations and analyses had compared with test results measured in lab. Under three different flow inlet cases shows that the development of boundary layer near convex side of wall are differ from the one near concave side of wall. Pressure...

Two dimensional internal flow near a curved wall with positive pressure gradient is discussed in this paper based on boundary-layer theory. A technical approach for calculating development of turbulent boundary-layer is presented and its test data are also given. Theoretical calculations and analyses had compared with test results measured in lab. Under three different flow inlet cases shows that the development of boundary layer near convex side of wall are differ from the one near concave side of wall. Pressure distributions along convex side of wall are more even and maximum pressure gradient on there appears later than along concave side of wall as the local loss coefficients for fronter are lower than later. Test data shows good agreement with calculating results discoverd subsequently. Brief introducing about the experiment set and test way are also included.