Experimental Investigation of Flow Induced Rotation of Hinged Plates With Shapes to Avoid Fluttering

2011 ◽  
Author(s):  
Antonio Carlos Fernandes ◽  
Sina Mirzaei Sefat ◽  
Fabio Moreira Coelho ◽  
Amanda Silva Albuquerque
Keyword(s):  
Experimental Investigation ◽  
Flat Plate ◽  
Flow Velocity ◽  
Natural Frequency ◽  
Dimensional Analysis ◽  
Vertical Axis ◽  
Incoming Flow ◽  
Stabilizing Effect ◽  
Plate Width ◽  
Angle Of Rotation

This paper addresses the flow induced rotation phenomena of plates hinged to allow flow induced rotating about their vertical axis. Different transversal shape configurations are studied. The aim of this study is to simplify the fluttering problem that may occur with falling objects in water during installation of offshore devices. The investigation intent is to propose an optimized configuration for stabilizing the fluttering motion of pendulous installation method of manifolds. The experiments and dimensional analysis confirmed that natural frequency is linearly proportional to the incoming flow velocity and inversely proportional to the flat plate width, and also the equivalent harmonic angle of rotation for small oscillation angles is approximately constant in different velocities. Experiments show that the bluffer plates (plate with two stabilizers and plate with stabilizers and nose), by increasing of period of rotation and also decreasing of equivalent harmonic angle of rotation have stabilizing effect in the fluttering motion of falling objects.

Noise Generated by Cavitation in Orifice Plates

1989 ◽  
Vol 111 (3) ◽  
pp. 278-289 ◽  
Author(s):  
S. R. Bistafa ◽  
G. C. Lauchle ◽  
G. Reethof
Keyword(s):  
Experimental Investigation ◽  
Flow Velocity ◽  
Dimensional Analysis ◽  
Cavitation Number ◽  
Turbulent Shear ◽  
Scaling Relations ◽  
Source Strength ◽  
Acoustic Source ◽  
Acoustic Performance ◽  
Reciprocity Method

An experimental investigation of the noise generated by cavitation in turbulent shear flows produced by confined sharp-edged orifice plates is reported. The acoustic source strength of cavitation was determined by means of reciprocity type measurements. Two experimental checks of the reciprocity method were performed. Proposed scaling relations, derived from dimensional analysis, were empirically adjusted and used to predict prototype acoustic performance based on the results of model tests. The dependence of the acoustic source strength on flow velocity and cavitation number was determined experimentally and compared with similar results reported in the literature.

Simulation of Fluttering and Autorotation Motion of Vertically Hinged Flat Plate

2015 ◽  
Author(s):  
Ali Bakhshandeh Rostami ◽  
Antonio Carlos Fernandes
Keyword(s):  
Reynolds Number ◽  
Flat Plate ◽  
Dimensional Analysis ◽  
Time Domain ◽  
Rotational Motion ◽  
Small Amplitude ◽  
Transition Point ◽  
Vertical Axis ◽  
The Body ◽  
Rotating Plate

This paper is dedicated to the simulation of fluttering (oscillatory) and tumbling (rotational) phenomenon that may occur during the flow induced rotation in the water or air current. Fluttering is the oscillation of body about an axis and the tumbling, better called here as autorotation, is a name given to the case when the body turns continuously around the axis. This work describes the simulation of these phenomena by a nonlinear time domain code on freely rotating plate about a fixed vertical axis. The dimensional analysis proves that the rotational motion induced by flow is governed essentially by the dimensionless moment of inertia (I*) and Reynolds number. For Reynolds number less than 15000, plate experiences small amplitude fluttering motion that is independent of I*. It is shown that by increasing I* the fluttering bifurcates to autorotation, with a transition point that is approximately independent of Reynolds number and is such that I*=0.083.

Flow through axial-flow-turbomachinery blading

2018 ◽  
Author(s):  
Marcel Escudier
Keyword(s):  
Flow Velocity ◽  
Compressible Flow ◽  
Dimensional Analysis ◽  
Incompressible Flow ◽  
Compressible Fluid ◽  
Axial Flow ◽  
Linear Cascade ◽  
Dimensional Parameters ◽  
Flow Through

This chapter is concerned primarily with the flow of a compressible fluid through stationary and moving blading, for the most part using the analysis introduced in Chapter 11. The principles of dimensional analysis are applied to determine the appropriate non-dimensional parameters to characterise the performance of a turbomachine. The analysis of incompressible flow through a linear cascade of aerofoil-like blades is followed by the analysis of compressible flow. Velocity triangles for flow relative to blades, and Euler’s turbomachinery equation, are introduced to analyse flow through a rotor. The concepts introduced are applied to the analysis of an axial-turbomachine stage comprising a stator and a rotor, which applies to either a compressor or a turbine.

Experimental investigation on tilt stabilizing effect of external toroidal field in low aspect ratio tokamak

1997 ◽  
Vol 4 (2) ◽  
pp. 315-322 ◽  
Author(s):  
A. Morita ◽  
Y. Ono ◽  
M. Katsurai ◽  
M. Yamada ◽  
S. Yoshikawa
Keyword(s):  
Experimental Investigation ◽  
Aspect Ratio ◽  
Toroidal Field ◽  
Low Aspect Ratio ◽  
Stabilizing Effect

Numerical study of the aerodynamic and power characteristics of the cycloidal rotor, under incoming flow

2019 ◽  
pp. 25-34
Author(s):  
Александр Анатольевич Дектерев ◽  
Артем Александрович Дектерев ◽  
Юрий Николаевич Горюнов
Keyword(s):  
Flow Velocity ◽  
Numerical Study ◽  
Lift Coefficient ◽  
Simulation Method ◽  
Aerodynamic Characteristics ◽  
Incoming Flow ◽  
Ansys Fluent ◽  
Energy Characteristics ◽  
Power Characteristics ◽  
Calculation Results

Исследование направлено на разработку и апробацию методики численного моделирования аэродинамических и энергетических характеристик циклоидального ротора. За основу взята конфигурация ротора IAT21 L3. Для нее с использованием CFD-пакета ANSYS Fluent построена математическая модель и выполнен расчет. Проанализировано влияние скорости набегающего потока воздуха на движущийся ротор. Математическая модель и полученные результаты исследования могут быть использованы при создании летательных аппаратов с движителями роторного типа. This article addresses the study of the aerodynamic and energy characteristics of a cycloidal rotor subject to the influence of the incoming flow. Cycloidal rotor is one of the perspective devices that provide movement of aircrafts. Despite the fact that the concept of a cycloidal rotor arose in the early twentieth century, the model of a full-scale aircraft has not been yet realized. Foreign scientists have developed models of aircraft ranging in weight from 0.06 to 100 kg. The method of numerical calculation of the cycloidal rotor from the article [1] is considered and realized in this study. The purpose of study was the development and testing of a numerical simulation method for the cycloidal rotor and study aerodynamic and energy characteristics of the rotor in the hovering mode and under the influence of the oncoming flow. The aerodynamic and energy characteristics of the cycloidal rotor, rotating at a speed of 1000 rpm with incoming flow on it with velocities of 20-80 km/h, were calculated. The calculation results showed a directly proportional increase of thrust with an increase of the incoming on the rotor flow velocity, but the power consumed by the rotor was also increased. Increase of the incoming flow velocity leads to the proportional increasing of the lift coefficient and the coefficient of drag. Up to a speed of 80 km/h, an increase in thrust and power is observed; at higher speeds, there is a predominance of nonstationary effects and difficulties in estimating the aerodynamic characteristics of the rotor. In the future, it is planned to consider the 3D formulation of the problem combined with possibility of the flow coming from other sides.

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