The effect of fine particles on turbulence damping and reduction of flow friction coefficient in ribleted pipes, have been investigated experimentally. Tests have been conducted in a ribleted pipe with hydraulic diameter of 18.6 mm, and 20 stream wise riblets of 1.8 mm depth, along the pipe. Flows of water tap with Reynolds number from 5000 to 30000 were compared with flows containing silt-clay...

There are dierent ways to code the geodesic flows on surfaces with negative curvature. Such code spaces give a useful tool to verify the dynamical properties of geodesic flows. Here we consider special subspaces of geodesic flows on Hecke surface whose arithmetic codings varies on a set with innite alphabet. Then we will compare the topological complexity of them by computing their topological ...

in the maximum flow network interdiction problem, an attacker attempts to minimize the maximum flow by interdicting flow on the arcs of network. in this paper, our focus is on the nodal interdiction for network instead of the arc interdiction. two path inequalities for the node-only interdiction problem are represented. it has been proved that the integrality gap of relaxation of the maximum fl...

The main purpose of this paper is to establish a relation between universality of certain P-compactifications of a semitopological semigroup and their corresponding enveloping semigroups. In particular, we show that if we take P to be the property that the enveloping semigroup of a compactification of a semitopological semigroup s is left simple, a group, or the trivial singleton semigroup, t...

iranian islamic gardens like almost every cultures, represent beauty and happiness and improve the public perception. it has also special geometry with philosophical concept related to islam’s doctrine that is the focus of this research. following quran’s contents, paradise is a beautiful sophisticated garden that something flows under its trees. so the comparison between the somatic geometry o...

In the theory of traffic flows the main characteristics are: intensity, speed, and density.  They make it possible to use hydrodynamic models. In connection with the development of modern highways and road networks, traffic flows behavior is becoming more and more complex and diverse. In particular, the B.Kerner studies have shown that the laminar solution of hydrodynamic models is poorly corre...

We give a symbolic construction of Shunji Ito’s “transversal flow for a subshift of finite type” [I], along the lines of Vershik’s construction of an adic transformation. We then show how these flows arise naturally in the symbolic coding of horocycle flows on non-compact hyperbolic surfaces with finite area.

Arterial stenosis, for example Atherosclerosis, is one of the most serious forms of arterial disease in the formation of which hemodynamic factors play a significant role. In the present study, a 3-D rigid carotid artery with axisymmetric stenosis with 75% reduction in cross-sectional area is considered. Laminar blood flow is assumed to have both Newtonian and non-Newtonian behavior (generalize...

A numerical study of 3D electrokinetic flows through micromixers was performed. The micromixers considered here consisted of heterogeneous rectangular microchannels with prescribed patterns of zeta-potential at their walls. Numerical simulation of electroosmotic flows within heterogeneous channels requires solution of the Navier-Stokes, Ernest-Plank and species concentration equations. It is kn...