The present study examines scour geometry and turbulent flow characteristics around circular and oblong piers in alluvial channel with downward seepage.Experiments were conducted in plane sand bed of non-uniform sand ...The present study examines scour geometry and turbulent flow characteristics around circular and oblong piers in alluvial channel with downward seepage.Experiments were conducted in plane sand bed of non-uniform sand under no seepage,10%seepage and 15%seepage conditions.Scour depth at oblong pier is significantly lesser than the scour depth at circular one.However,the scour depth at both piers reduces with downward seepage.The measurements show that the velocity and Reynolds stresses are negative near the bed at upstream of piers where the strong reversal occurs.At downstream of oblong pier near the free surface,velocity and Reynolds stresses are less positive;whereas,they are negative at downstream of circular pier.The streamline shape of oblong pier leads to reduce the strength of wake vortices and consequently reversal flow at downstream of pier.With application of downward seepage turbulent kinetic energy is decreasing.The results show that the wake vortices at oblong pier are weaker than the wake vortices at circular pier.The strength of wake vortices diminishes with downward seepage.The Strouhal number is lesser for oblong pier and decreases with downward seepage for both oblong and circular piers.展开更多
On the basis of hypothesis of replacement and the vector formula of Newton’s law for a viscous fluid the way of a finding of resistance a slow flow by an incompressible fluid of bodies of the various form is represen...On the basis of hypothesis of replacement and the vector formula of Newton’s law for a viscous fluid the way of a finding of resistance a slow flow by an incompressible fluid of bodies of the various form is represented. Application of an offered way to calculation of a flow of various bodies is shown: a sphere, a cylinder, a oblong ellipsoid, a flat plate. Comparison with results of other authors is given.展开更多
文摘The present study examines scour geometry and turbulent flow characteristics around circular and oblong piers in alluvial channel with downward seepage.Experiments were conducted in plane sand bed of non-uniform sand under no seepage,10%seepage and 15%seepage conditions.Scour depth at oblong pier is significantly lesser than the scour depth at circular one.However,the scour depth at both piers reduces with downward seepage.The measurements show that the velocity and Reynolds stresses are negative near the bed at upstream of piers where the strong reversal occurs.At downstream of oblong pier near the free surface,velocity and Reynolds stresses are less positive;whereas,they are negative at downstream of circular pier.The streamline shape of oblong pier leads to reduce the strength of wake vortices and consequently reversal flow at downstream of pier.With application of downward seepage turbulent kinetic energy is decreasing.The results show that the wake vortices at oblong pier are weaker than the wake vortices at circular pier.The strength of wake vortices diminishes with downward seepage.The Strouhal number is lesser for oblong pier and decreases with downward seepage for both oblong and circular piers.
文摘On the basis of hypothesis of replacement and the vector formula of Newton’s law for a viscous fluid the way of a finding of resistance a slow flow by an incompressible fluid of bodies of the various form is represented. Application of an offered way to calculation of a flow of various bodies is shown: a sphere, a cylinder, a oblong ellipsoid, a flat plate. Comparison with results of other authors is given.
