The interaction between free surface flow and structure is investigated using a new level set immersed boundary method.The incorporation of an improved immersed boundary method with a free surface capture scheme imple...The interaction between free surface flow and structure is investigated using a new level set immersed boundary method.The incorporation of an improved immersed boundary method with a free surface capture scheme implemented in a Navier-Stokes solver allows the interaction between fluid flow with free surface and moving body/bodies of almost arbitrary shape to be modelled.A new algorithm is proposed to locate exact forcing points near solid boundaries,which provides an accurate numerical solution.The discretized linear system of the Poisson pressure equation is solved using the Generalized Minimum Residual(GMRES)method with incomplete LU preconditioning.Uniform flow past a cylinder at Reynolds number Re=100 is modelled using the present model and results agree well with the experiment and numerical data in the literature.Water exit and entry of a cylinder at the prescribed velocity is also investigated.The predicted slamming coefficient is in good agreement with experimental data and previous numerical simulations using a ComFlow model.The vertical slamming force and pressure distribution for the free falling wedge is also studied by the present model and comparisons with available theoretical solutions and experimental data are made.展开更多
Using the spatial structure of the external staggered split-level panel layout,a combined support technology for adjacent roadways was developed and analyzed for a rock bolt and anchor cable mechanism.The influence of...Using the spatial structure of the external staggered split-level panel layout,a combined support technology for adjacent roadways was developed and analyzed for a rock bolt and anchor cable mechanism.The influence of the side rock bolt and anchor cable parameters on the mechanical properties of the anchorage body and the support stress distribution of the lateral coal body were revealed using the FLAC3D software.The optimal support parameters of the side rock bolts and anchor cables were subsequently determined,and the support effect of gob-side entry in a mining scenario was verified.The results show that the support of the side rock bolts and anchor cables improves the mechanical properties and stress state of the anchorage body,producing a good protective effect on the coal body of the air-intake entry roof and side wall.This is beneficial to the stability of the side wall and the realization of the suspension effect for roof rock bolts and anchor cables,which in turn makes the surrounding rock maintenance of the gob-side entry to a thick coal seam more favorable.展开更多
This study extends the ambit of the debate on electricity transitionby specifically identifying possible policy entry points through which transformative and enduring changes can be made in the electricity and socio-e...This study extends the ambit of the debate on electricity transitionby specifically identifying possible policy entry points through which transformative and enduring changes can be made in the electricity and socio-economic systems to facilitate the transition process.Guided by the"essence"of the multi-level perspective-a prominent framework for the study of energy transition,four such entry points have been identified:1)destabilising the dominant,fossil fuel-based electricity regime to create room for renewable technologies tobreak through;2)reconfiguring the electricity regime,which encompasses technology,short-term operational practices and long-term planning processes,to improve flexibility for accommodating large outputs from variable renewable sources whilst maintaining supply security;3)addressing the impactofcoal power phase-outon coal mining regions in terms of economic development and jobs;and 4)facilitating a shift in transition governance towards a learning-based,reflexive process.Specific areas for policy interventions within each of these entry points have also been discussed in the paper.展开更多
基金the support of the South West of England Regional Development Agency in funding this project through Peninsular Research Institute for Marine Renewable Energy(http://www.primare.org/).
文摘The interaction between free surface flow and structure is investigated using a new level set immersed boundary method.The incorporation of an improved immersed boundary method with a free surface capture scheme implemented in a Navier-Stokes solver allows the interaction between fluid flow with free surface and moving body/bodies of almost arbitrary shape to be modelled.A new algorithm is proposed to locate exact forcing points near solid boundaries,which provides an accurate numerical solution.The discretized linear system of the Poisson pressure equation is solved using the Generalized Minimum Residual(GMRES)method with incomplete LU preconditioning.Uniform flow past a cylinder at Reynolds number Re=100 is modelled using the present model and results agree well with the experiment and numerical data in the literature.Water exit and entry of a cylinder at the prescribed velocity is also investigated.The predicted slamming coefficient is in good agreement with experimental data and previous numerical simulations using a ComFlow model.The vertical slamming force and pressure distribution for the free falling wedge is also studied by the present model and comparisons with available theoretical solutions and experimental data are made.
基金National Natural Science Foundation of Surface Project of China(Grant Nos.5177428952074291)+2 种基金The National Natural Science Foundation of the Youth Science Foundation of China(Grant No.51404270)The Fundamental Research Funds for the Central Universities(Grant No.2011QZ06)The Open Fund of State Key Laboratory of Coal Resources in Western China(Grant No.SKLCRKF1903).
文摘Using the spatial structure of the external staggered split-level panel layout,a combined support technology for adjacent roadways was developed and analyzed for a rock bolt and anchor cable mechanism.The influence of the side rock bolt and anchor cable parameters on the mechanical properties of the anchorage body and the support stress distribution of the lateral coal body were revealed using the FLAC3D software.The optimal support parameters of the side rock bolts and anchor cables were subsequently determined,and the support effect of gob-side entry in a mining scenario was verified.The results show that the support of the side rock bolts and anchor cables improves the mechanical properties and stress state of the anchorage body,producing a good protective effect on the coal body of the air-intake entry roof and side wall.This is beneficial to the stability of the side wall and the realization of the suspension effect for roof rock bolts and anchor cables,which in turn makes the surrounding rock maintenance of the gob-side entry to a thick coal seam more favorable.
基金This work was supported by the National Natural Science Foundation of China(Grant No.72174056).
文摘This study extends the ambit of the debate on electricity transitionby specifically identifying possible policy entry points through which transformative and enduring changes can be made in the electricity and socio-economic systems to facilitate the transition process.Guided by the"essence"of the multi-level perspective-a prominent framework for the study of energy transition,four such entry points have been identified:1)destabilising the dominant,fossil fuel-based electricity regime to create room for renewable technologies tobreak through;2)reconfiguring the electricity regime,which encompasses technology,short-term operational practices and long-term planning processes,to improve flexibility for accommodating large outputs from variable renewable sources whilst maintaining supply security;3)addressing the impactofcoal power phase-outon coal mining regions in terms of economic development and jobs;and 4)facilitating a shift in transition governance towards a learning-based,reflexive process.Specific areas for policy interventions within each of these entry points have also been discussed in the paper.
