ISSN:0022-1686    

DOI:10.1080/00221689809498373

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This paper describes the possibilities for modeling of non-uniform temperature behavior around the metal fuel pins in reactors cooled by liquid metal using water. The temperature non-uniformities arise due to nonsymmetric heat removal from the pin.

ISSN:0022-1686    

DOI:10.1080/00221689809498374

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

The equations of continuity, momentum and energy are derived, incorporating depth-dependent correction factors for velocity distributions over compound cross sections. It is shown that the friction slope and the energy slope are equivalent in steady uniform flow but not in unsteady flow. The difference between the two forms is explained and reasons are given for the preferential use of the momentum equation. Comparisons of backwater profiles are presented.

ISSN:0022-1686    

DOI:10.1080/00221689809498375

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This paper proposes a new equation for predicting the transversal mixing coefficient giving the mean values of the longitudinal mixing coefficient, the quantity of flow, the depth of flow and the ratio width to depth of the river. This equation is developped from the relation between the transversal and the longitudinal coefficient proposed by the authors in 1994 taking into account all the data found in litterature of all the mixing coefficients (transversal and longitudinal) measured simultanously with the same hydraulic conditions. The proposed formula expresses the transversal coefficient as a fonction of the longitudinal coefficient. This new formula is more representative of the experimental results and confirms the trend of recent years to use the product of coefficients (KlKtrather than Kl/Kt) to describe the interaction between the transversal and the longitudinal mixing coefficients.

ISSN:0022-1686    

DOI:10.1080/00221689809498376

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This paper uses the model of transient flow to analyse the mechanism of fluctuating pressure propagation within the cracks of bed rock and the cause of fluctuating uplift generation in details. A predicting formula for the maximum fluctuating uplift on rock blocks in a scour pool is deduced. To confirm the theoretical results, fluctuating uplift on different sized rock blocks at the bottom of scour pool downstream of the Three Gorges spillway model are measured.

ISSN:0022-1686    

DOI:10.1080/00221689809498377

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This paper presents the results of a laboratory study on the flow regimes at a rectangular drop with a subcritical approach flow, when the tailwater depth approaches the height of the drop or exceeds it. It was found that the flow at the drop could be in either the impinging jet or surface flow regime. An empirical scheme has been developed for predicting the occurrence of either of these regimes, which was found to be affected by the direction of change of the tailwater depth.

ISSN:0022-1686    

DOI:10.1080/00221689809498378

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Most rivers exhibit a tendency for the characteristic size of'the bed material to become finer in the downstream direction. In addition, most river sediments also exhibit a paucity of material in the pea gravel range. Because of this paucity the transition in the downstream direction from a gravel-bed stream to a sand-bed stream is usually rather abrupt, and is often marked by a discontinuity in bed slope and stream morphology as well. If the front marking the gravel-sand transition is not to prograde continuously in the direction of the point at which base level is established, e.g. the ocean, then some mechanism must operate to arrest it in place. Here two such mechanisms are examined; abrasion of gravel and basin subsidence (or alternatively base level rise). It is found that either one or a combination of the two can act to stabilize the spatial location of the gravel-sand transition. The present paper is devoted to a simplified analytical solution to the problem that renders the structure of the formulation relatively transparent. A complete numerical solution that more realistically describes the field manifestation is presented in a companion paper.

ISSN:0022-1686    

DOI:10.1080/00221689809498379

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

This paper analyses sanitary landfills as biochemical reactors and particularly the significance of water balance and multi-phase flow in a landfill system. Field studies reveal a strong coupling between water content and landfill gas production. This study focuses on evaluation of field observations on water content, temperature, gas and leachate production in specially designed and operated landfills. Theoretical simulation of multiphase flow conditions - water and gas transport - has been carried out for different components of the landfill system. Top cover as barrier to gas exchange, 1-D heat transport and heat source distribution and water percolation reproducing mechanical dispersion due to presence of waste elements in the sanitary landfill are modelled to improve insight into the overall performance of sanitary landfills.

ISSN:0022-1686    

DOI:10.1080/00221689809498380

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

A companion paper presented the development of a three-dimensional numerical model to simulate the behaviour of buoyant oil jets that result from underwater accidents. The numerical model was developed based on a Lagrangian integral technique. The model can simulate the behaviour of oil in stratified or unstratified ocean environments. The presence of a multi-directional ambient current is considered. The fluid in the buoyant jet can be a liquid, gas. or liquid/gas mixture, which is typical of many underwater oil-related accidents. The model formulation includes the diffusion and dissolution of oil from the jet to the ambient environment.

ISSN:0022-1686    

DOI:10.1080/00221689809498381

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor

摘要:

Conflicts between development and environmental protection is often inevitable. The paper, based upon the results of a NATO-workshop, defines the problems and the sustainability criteria. With these sharpened definitions it can be expected that conflicts can be easier discussed between the different parties which eases optimal decisions: conflicts are reduced to disputes and disputes are reduced to low-level issues.

ISSN:0022-1686    

DOI:10.1080/00221689809498382

出版商:Taylor & Francis Group    

年代:1998

数据来源: Taylor