The ability of the three-dimensional Navier-Stokes method, PAB3D, to simulate the e ect of Reynolds number variation using non-linear explicit algebraic Reynolds stress turbulence modeling was assessed. Subsonic at plate boundary-layer ow parameters such as normalized velocity distributions, local and average skin friction, and shape factor were compared with DNS calculations and classical theo...

Small vegetated drainage ditches play an important role in water and nutrient removal, but may cause water blocking problems. The aim of this study was to investigate vegetated drainage ditches’ hydraulic and wetland hydraulic characters. Field experiment were carried out, small drainage ditches with Juncus, Zizania latifolia, and Acorus calamus were selected under different water flows, and a ...

In many industrial equipment such as boilers and heat exchangers, the cylindrical tubes are exposed to the gas- liquid two phase flow. For any immersed body in flow field vortex shedding is created with a frequency that may be constant or variable, according to conditions such as flow rates, geometry of body, and etc. The failure will happen in the equipment, when this frequency is close to...

Abstract The thrust producing performance and efficiency of an SD8020 oscillating foil with a symmetrical saw-tooth angle of attack pitching profile was studied through force and torque measurements, as well as dye flow visualization, in the water tunnel at low Reynolds number of 13,000-16,000. The propulsive efficiency and thrust coefficient of the pitching foil were determined as a function o...

The objective of this paper is to examine the effectiveness of wall oscillation as a control scheme of drag reduction. Two flow configurations are considered: constant flow rate and constant mean pressure gradient. The Navier-Stokes equations are solved using Fourier-Chebyshev spectral methods and the oscillation in sinusoidal form is enforced on the walls through boundary conditions for the sp...

In this work, for better understanding of drug delivery systems, blood flow over a ceramic nanoparticle is investigated through microvessels. Drug is considered as a nanoparticle coated with the rigid ceramic. Due to the low characteristic size in the microvessel, the fluid flow is not continuum and the no-slip boundary condition cannot be applied. To solve this problem lattice Boltzmann method...

This study concerns numerical simulation, modeling and optimization of aerodynamic stall control using a synthetic jet actuator. Thenumerical simulation was carried out by a large-eddy simulation that employs a RNG-based model as the subgrid-scale model. The flow around a NACA0015 airfoil, including a synthetic jet located at 10 % of the chord, is studied under Reynolds number Re = 12.7 × 106 a...

One of the newest of viscoelastic RANS turbulence models for drag reducing channel flow with polymer additives is studied in different flow and rheological properties. In this model, finitely extensible nonlinear elastic-Peterlin (FENE-P) constitutive model is used to describe the viscoelastic effect of polymer solution and turbulence model is developed in the k-ϵ-(ν^2 ) ̅-f framework. The geome...

A method for accurately measuring the drag associated with a protuberance on an aircraft has been devised and implemented in a wind tunnel using a C-130 model. The C-130 aircraft has been heavily modified for various different configurations and the impact that these modifications have had on the aerodynamic performance of the aircraft has not been well documented. This paper describes a method...

This paper presents results of several large-eddy simulations LES of turbulent flow in an open channel through staggered arrays of rigid, emergent cylinders, which can be regarded as idealized vegetation. In this study, two cylinder Reynolds numbers, RD =1,340 and RD=500, and three vegetation densities are considered. The LES of the lowest density and at RD=1,340 corresponds to a recently compl...