Flow resistance due to vegetation may greatly affect the conveyance of a channel, and thus evaluating the resistance is a critical task in river engineering and restoration. Therefore, flow resistance of natural willows and sedges was studied in a laboratory flume. The aim was to investigate, how type, density and combination of vegetation, flow depth and velocity influence vegetal drag or fric...

In the analysis of orthogonal cutting process using FE simulations, predictions are greatly influenced by two major factors; a) flow stress characteristics of work material at cutting regimes and b) friction characteristics mainly at the chip-tool interface. The influence of work material flow stress upon FE simulations may be less or even none when there is a constitutive model for work materi...

in this research, the effect of surface roughness and bubble injection on skin friction and hydrodynamic drag force has been numerically considered. this research is based on taylor-couette flow. considered flow includes two concentric cylinders which internal cylinder is movable and external is immovable. the effective equations on the flow includes: equations of momentum, continuous, turbulen...

in order to increase the efficiency of the conveyance of the granular solids, a new experimental set-up is designed. the test rig has longitudinal trapezoidal slots in its conveying pipes. through experimentation, a correlation for friction factor in terms of solid mass flow rate, fluid flow rate and froude number is presented. it is shown that the mixture friction factor for pipes with inner t...

–Friction stir welding is a solid state welding technology used for welding low melting point metals, such as Al, Mg and its alloys. Later welding was conducted on dissimilar metals which also produced a better defect free joint. Tool design and welding parameters contributes a major role for producing a better weld. Material flow and friction heat are the factors that the internal factor for t...

  Micro scale gas flows has attracted significant research interest in the last two decades. In this research, the fluid flow of gases in the stepped micro-channel at a wide range of Knudsen number has been analyzed with using the Lattice Boltzmann (MRT) method. In the model, a modified second-order slip boundary condition and a Bosanquet-type effective viscosity are used to consider the veloci...

Nowadays, the Colebrook equation is used as a mostly accepted relation for the calculation of fluid flow friction factor. However, the Colebrook equation is implicit with respect to the friction factor (λ). In the present study, a noniterative approach using Artificial Neural Network (ANN) was developed to calculate the friction factor. To configure the ANN model, the input parameters of the Re...

We examine the characteristics of helical flow in a concentric annulus with radii ratios of 0.52 and 0.9, whose outer cylinder is stationary and inner cylinder is rotating. Pressure losses and skin friction coefficients are measured for fully developed flows of water and a 0.4% aqueous solution of sodium carboxymethyl cellulose (CMC), when the inner cylinder rotates at the speed of 0~62.82 rad/...

Computational study was carried out to determine average heat transfer coefficients and friction factors for turbulent flow through rectangular ducts with ribs. A commercial finite volume package ANSYS FLUENT 12.1 is used to analyze and visualize the nature of the flow across the ribbed duct The fluid in the duct was air, and the average heat transfer coefficients were determined by measuring t...

In the analysis of orthogonal cutting process using finite element (FE) simulations, predictions are greatly influenced by two major factors; a) flow stress characteristics of work material at cutting regimes and b) friction characteristics mainly at the tool-chip interface. The uncertainty of work material flow stress upon FE simulations may be low when there is a constitutive model for work m...