As a model for molecular traffic control we investigate the diffusion of hard core particles in crossed single-file systems. We consider a square lattice of single-files being connected to external reservoirs. The (vertical) alpha channels, carrying only A particles, are connected to reservoirs with constant density rho(A). B particles move along the (horizontal) beta channels, which are connec...

Dam construction is widespread, changing the hydrological and biogeochemical conditions thereby bacterial communities in rivers of earth. To date, knowledge lacking about cascade reservoirs. Here, we investigated potential functions nine hydropower reservoirs 1290 km upper Mekong River (Lancang China). Along reservoir cascade, water temperature, rather than presence dams, was main cause for geo...

We consider surface gravity currents in fresh water where the temperatures of the current and the ambient are on opposite sides of the temperature of maximum density. Buoyancy reversal may occur in the current, due to entrainment of ambient water to produce a mixture that is denser than the ambient. Using an empirical parametrisation of entrainment in lock-release gravity currents, the distance...

The increasing impact of both climatic change and human activities on global river systems necessitates an increasing need to identify and quantify the various drivers and their impacts on fluvial water and sediment discharge. Here we show that mean Yangtze River water discharge of the first decade after the closing of the Three Gorges Dam (TGD) (2003-2012) was 67 km(3)/yr (7%) lower than that ...

We discuss here the evolution of vorticity and potential vorticity (PV) for a bottom current crossing a marine channel in shallow-water approximation, focusing on the effect of friction and mixing. The purpose of this research is indeed to investigate the role of friction and vertical entrainment on vorticity and PV spatial evolution in channels or straits when along-channel morphology variatio...

In light of previous numerical studies demonstrating a strong sensitivity of the strength of thermohaline circulation to the representation of overflows in ocean general circulation models, the dynamics of bottom gravity currents are investigated using a two-dimensional, nonhydrostatic numerical model. The model explicitly resolves the Kelvin–Helmholtz instability, the main mechanism of mixing ...

Density Current is formed when a fluid with heavier density than the surrounding fluid flows down an inclined bed. These types of flows are common in nature and can be produced by; salinity, temperature inhomogeneities, or suspended particles of silt and clay. Driven by the density difference between inflow and clear water in reservoirs, density current plunges clear water and moves towards a d...

Lock–release laboratory experiments are performed to examine saline and particleladen flows down a slope into both constant-density and linearly stratified ambients. Both hypopycnal (surface-propagating) currents and hyperpycnal (turbidity) currents are examined, with the focus being upon the influence of ambient stratification on turbidity currents. Measurements are made of the along-slope fro...

background: dams are one of the most important manmade buildings to provide of drinking water. in order to manage of water quality in dams reservoirs, the recognition of phenomena that occurred in it is essential. thermal stratification is one of the major problems that decrease the water quality of dam. the aim of this study was to investigate thermal stratification of ekbatan dam (hamadan) as...