Simulation of an underwater glider to investigate the effect of angle of attack on the hydrodynamic coefficients such as lift, drag, and torque. Due to the vital role of these coefficients in designing the controllers of a glider and to obtain an accurate result, this simulation has been studied at a range of operating velocities. The total length of the underwater glider with two wings is 900 ...

This paper investigates the influence of two crossovers on twin bare spheroids in close proximity. Firstly, to examine the impact of the crossovers to the flow behaviour and overall drag coefficient of spheroids. Secondly, to compare the drag coefficient for various speeds. The CFD RANS-SST with a commercial code ANSYS CFX simulation is performed for the fully submerged twin spheroids with tran...

We investigate the phenomenon of drag reduction in a viscoelastic fluid model of dilute polymer solutions. By means of direct numerical simulations of the three-dimensional turbulent Kolmogorov flow we show that drag reduction takes place above a critical Reynolds number Re(c). An explicit expression for the dependence of Re(c) on polymer elasticity and diffusivity is derived. The values of the...

To understand the basic characteristics of the observed S-shaped wind profile and the exponential flux profile within forest canopies, three hypotheses are postulated. The relationship between these fundamental profiles is well established by combining the postulated hypotheses with momentum equations. Robust agreements between theoretical predictions and observations indicate that the nature o...

The flow of a non-Newtonian, power-law fluid, directed normally to long, two-dimensional horizontal bodies, is considered in the present note. It is found that for low Reynolds numbers (Re ≤ 0.1) and a low power-law index (shear-thinning fluids) the drag coefficient always obeys the relationship cD = A/Re, whereas at a high power-law index (shear-thickening fluids) the drag coefficient tends to...

Nylon (PA) netting is widely used in purse seines and other fishing gears due to its high strength and good sinking performance. However, hydrodynamic properties of nylon netting of different characteristics are poorly understood. This study investigated hydrodynamic characteristics of nylon netting of different knot types and solidity ratios under different attack angles and flow velocities. I...

In many cases, a set of obstacles, such as bridge piers and abutments, are located in the river waterway. Bridge piers disrupt river’s normal flow, and the created turbulence and disturbance causes diversion of flow lines and creates rotational flow. Geometric shape and position of the piers with respect to flow direction and also number of piers and their spacing are effective on changing the ...

Submit Manuscript | http://medcraveonline.com Abbreviations: c: chord; u∞ : Free Stream Velocity; ν: Kinematic Viscosity; Re: Chord Reynolds number, ( ) / u c n ∞ = ; OGE: Out of the Ground Effect; GE: Ground Effect; Cd: Sectional Drag Coefficient; Cdp: Sectional Pressure Drag Coefficient; Cl: Sectional Lift Coefficient; Cl,max: Maximum Cl; l C α :Lift-Curve Slope; Cm: Sectional Pitching Moment...

Submit Manuscript | http://medcraveonline.com Abbreviations: c: chord; u∞ : Free Stream Velocity; ν: Kinematic Viscosity; Re: Chord Reynolds number, ( ) / u c n ∞ = ; OGE: Out of the Ground Effect; GE: Ground Effect; Cd: Sectional Drag Coefficient; Cdp: Sectional Pressure Drag Coefficient; Cl: Sectional Lift Coefficient; Cl,max: Maximum Cl; l C α :Lift-Curve Slope; Cm: Sectional Pitching Moment...

We present the results of an investigation of the drag force on a horizontal grid of bars moving vertically through a stratified fluid. A novel approach was used to calculate the drag, based on measurements of the terminal velocity of a freely rising grid. In the homogeneous case the drag coefficient of the grid is found to be approximately constant for a range of grid-based Reynolds numbers. I...