Flip buckets are commonly used to discharge flow away from a hydraulic structure into the downstream to dissipate energy.A new leak-floor flip bucket is presented,making the ski-jump water jet a typical long-narrow na...Flip buckets are commonly used to discharge flow away from a hydraulic structure into the downstream to dissipate energy.A new leak-floor flip bucket is presented,making the ski-jump water jet a typical long-narrow nappe.Based on the model experiments and numerical simulation,the flow pattern,formation process and mechanism of the leak-floor flip bucket are studied.The results show that cross section flow shape develops from the"Y-type"to"|-type",and this is because the natural pressure difference is generated when water flows through the leak-floor area and moves transversely from both sides to the center.Different from the slit-type flip bucket with sidewall contraction,the leak-floor flit bucket makes the water jet narrow and long without high pressure on the side walls of the flip bucket.Under the same jet length condition,the maximum sidewall pressure of the slit-type is 4.67 times that of the leak-floor flip bucket.The effects of flow discharge on the jet length are less significant for the leak-floor bucket than for the slit-type bucket.展开更多
The author studies two singular limits of the convective Navier-Stokes equations.The hydrostatic limit is first studied:the author shows the existence of global solutions with a convex pressure field and derives them ...The author studies two singular limits of the convective Navier-Stokes equations.The hydrostatic limit is first studied:the author shows the existence of global solutions with a convex pressure field and derives them from the convective Navier-Stokes equations as long as the pressure field is smooth and strongly convex.The (friction dominated) Darcy limit is also considered,and a relaxed version is studied.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.51379138&51179113)Sichuan Province Funds for Distinguished Young Scientists(Grant No.2013JQ0007)
文摘Flip buckets are commonly used to discharge flow away from a hydraulic structure into the downstream to dissipate energy.A new leak-floor flip bucket is presented,making the ski-jump water jet a typical long-narrow nappe.Based on the model experiments and numerical simulation,the flow pattern,formation process and mechanism of the leak-floor flip bucket are studied.The results show that cross section flow shape develops from the"Y-type"to"|-type",and this is because the natural pressure difference is generated when water flows through the leak-floor area and moves transversely from both sides to the center.Different from the slit-type flip bucket with sidewall contraction,the leak-floor flit bucket makes the water jet narrow and long without high pressure on the side walls of the flip bucket.Under the same jet length condition,the maximum sidewall pressure of the slit-type is 4.67 times that of the leak-floor flip bucket.The effects of flow discharge on the jet length are less significant for the leak-floor bucket than for the slit-type bucket.
基金supported by ANR contract OTARIE ANR-07-BLAN-0235the program "Optimal Transport"
文摘The author studies two singular limits of the convective Navier-Stokes equations.The hydrostatic limit is first studied:the author shows the existence of global solutions with a convex pressure field and derives them from the convective Navier-Stokes equations as long as the pressure field is smooth and strongly convex.The (friction dominated) Darcy limit is also considered,and a relaxed version is studied.
