Forces on Staggered Airfoil Cascades in Unsteady In-Phase Motion

1981 ◽  
Vol 103 (2) ◽  
pp. 299-306
Author(s):  
H. Shoji ◽  
H. Ohashi ◽  
N. H. Kemp
Keyword(s):  
Velocity Field ◽  
Conformal Mapping ◽  
Potential Flow ◽  
Approximate Solutions ◽  
Kutta Condition ◽  
Harmonic Motion ◽  
Flow Through ◽  
Stagger Angle ◽  
Analytical Expressions ◽  
Phase Motion

We consider incompressible potential flow through a cascade of staggered thin airfoils in general, unsteady, in-phase motion. With the assumptions of the Kutta condition and linearized wakes, exact analytical expressions are derived for pressure distribution, lift, and moment, using conformal mapping applied to the velocity field. The results are then specialized to harmonic motion, and applied to plunging, pitching, and sinusoidal gusts. All the results are expressed in closed-form as quadratures, and reduce to the well-known relations for thin airfoil theory, as the solidity decreases to zero. They agree with the unstaggered results of Kemp and Ohashi when the stagger angle is zero. Typical numerical results are given in the figures. They should serve as a measure of the accuracy of numerical or approximate solutions, as well as representing in a simple way the effects of stagger and solidity on unsteady cascade aerodynamics.

Forces on Unstaggered Airfoil Cascades in Unsteady In-Phase Motion

1976 ◽  
Vol 98 (3) ◽  
pp. 521-530 ◽  
Author(s):  
N. H. Kemp ◽  
H. Ohashi
Keyword(s):  
Flow Velocity ◽  
Incompressible Flow ◽  
Kutta Condition ◽  
Harmonic Motion ◽  
Thin Airfoil ◽  
Through Flow ◽  
Flow Through ◽  
Unsteady Effects ◽  
Analytical Expressions ◽  
Phase Motion

Incompressible flow through an unstaggered cascade in general, unsteady, in-phase motion is considered. By methods of thin-airfoil theory, using the assumptions of wakes trailing back at the through-flow velocity, and the Kutta condition, exact analytical expressions are derived for loading, lift and moment. As application, harmonic motion is considered for plunging, pitching, and sinusoidal gusts. Numerical values of lift and moment for these three cases are given graphically (tables are available from the authors). The results show strong analogies with isolated unsteady thin-airfoil theory. They should prove useful as simple examples of unsteady effects in cascades, and as check cases for other approximate or purely numerical analyses.

scholarly journals Unsteady free covection oscillatory couette flow through a porous medium with periodic wall temperature

2007 ◽  
Vol 38 (1) ◽  
pp. 93-102 ◽  
Author(s):  
P. Kumar Sharma ◽  
B. Kumar Sharma ◽  
R. C. Chaudhary
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Velocity Field ◽  
Free Stream ◽  
Approximate Solutions ◽  
Stream Velocity ◽  
Moving Plate ◽  
Flow Through ◽  
Periodic Temperature ◽  
Highly Porous

This communication investigates the effect of free convection on the heat transfer and the flow through a highly porous medium bounded by two vertical parallel porous plates. It is assume that free stream velocity oscillates in times about a constant mean. Assuming periodic temperature at the moving plate, the approximate solutions for velocity field, emperature field, skin-friction and the rate of heat transfer are obtained and discussed with the help of graphs and tables.

Velocity field in isothermal turbulent bubbly gas-liquid flow through a pipe

1996 ◽  
Vol 21 (5) ◽  
pp. 347-356 ◽  
Author(s):  
V. Velidandla ◽  
S. Putta ◽  
R. P. Roy
Keyword(s):  
Velocity Field ◽  
Liquid Flow ◽  
Flow Through ◽  
Gas Liquid Flow

Two-Dimensional Flow With Standing Vortexes in Ducts and Diffusers

1960 ◽  
Vol 82 (4) ◽  
pp. 921-927 ◽  
Author(s):  
Friedrich O. Ringleb
Keyword(s):  
Wind Tunnel ◽  
Potential Flow ◽  
Separation Control ◽  
Two Dimensional ◽  
Dimensional Flow ◽  
Princeton University ◽  
Two Dimensional Flow ◽  
Flow Through ◽  
Trapping Devices

The conditions for the equilibrium of two vortexes in a two-dimensional flow through a duct or diffuser are derived. Potential-flow considerations and a few basic results from viscous-flow theory are used for the discussion of the role of cusps as separation control and trapping devices for standing vortexes. The investigations are applied to cusp diffusers especially with regard to the wind tunnel of the James Forrestal Research Center of Princeton University.

Extrusion of stiffening ribs on body parts with local heating

2021 ◽  
pp. 72-74
Author(s):  
Keyword(s):  
Velocity Field ◽  
Stress Relaxation ◽  
Local Heating ◽  
Hot Extrusion ◽  
Body Parts ◽  
Calculation Results ◽  
Energy Equilibrium ◽  
Stiffening Ribs ◽  
Analytical Expressions ◽  
Kinetics Of

A scheme is proposed and analytical expressions are obtained for calculating the kinematics, pressure and damageability of the material during hot extrusion of ribs on body parts. The equations of states during creep, energy equilibrium, kinetics of material discontinuity are used. The calculation results are presented. Keywords: extrusion, local heating, stiffening rib, viscosity, plasticity, stress relaxation, pressure, velocity field [email protected], [email protected]

Approximate Solutions to a Cantilever Beam Using Optimal Homotopy Asymptotic Method

2013 ◽  
Vol 430 ◽  
pp. 22-26 ◽  
Author(s):  
Vasile Marinca ◽  
Nicolae Herisanu ◽  
Traian Marinca
Keyword(s):  
Small Parameter ◽  
Cantilever Beam ◽  
Asymptotic Method ◽  
Approximate Solutions ◽  
Lumped Mass ◽  
Engineering Problems ◽  
Approximate Frequency ◽  
Optimal Homotopy Asymptotic Method ◽  
Analytical Expressions

The response of a cantilever beam with a lumped mass attached to its free end subject to harmonical excitation at the base is investigated by means of the Optimal Homotopy Asymptotic Method (OHAM). Approximate accurate analytical expressions for the solutions and for approximate frequency are determined. This method does not require any small parameter in the equation. The obtained results prove that our method is very accurate, effective and simple for investigation of such engineering problems.

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