A simplified model for drag evaluation of a streamlined body with leading-edge damage

2021 ◽  
pp. 1-24
Author(s):  
Haoliang Yu ◽  
Umberto Ciri ◽  
Arif Malik ◽  
Stefano Leonardi
Keyword(s):  
Leading Edge ◽  
Simplified Model ◽  
Streamlined Body ◽  
Edge Damage

Fan Stability With Leading Edge Damage: Blind Prediction and Validation

2021 ◽  
Author(s):  
E. J. Gunn ◽  
T. Brandvik ◽  
M. J. Wilson ◽  
R. Maxwell
Keyword(s):  
Supersonic Flow ◽  
High Speed ◽  
Leading Edge ◽  
Rotating Stall ◽  
Stall Inception ◽  
Blind Prediction ◽  
Edge Damage ◽  
The Impact ◽  
Operating Points ◽  
Relative Flow

Abstract This paper considers the impact of a damaged leading edge on the stall margin and stall inception mechanisms of a transonic, low pressure ratio fan. The damage takes the form of a squared-off leading edge over the upper half of the blade. Full-annulus, unsteady CFD simulations are used to explain the stall inception mechanisms for the fan at low- and high-speed operating points. A combination of steady and unsteady simulations show that the fan is predicted to be sensitive to leading edge damage at low speed, but insensitive at high speed. This blind prediction aligns well with rig test data. The difference in response is shown to be caused by the change between subsonic and supersonic flow regimes at the leading edge. Where the inlet relative flow is subsonic, rotating stall is initiated by growth and propagation of a subsonic leading edge flow separation. This separation is shown to be triggered at higher mass flow rates when the leading edge is damaged, reducing the stable flow range. Where the inlet relative flow is supersonic, the flow undergoes a supersonic expansion around the leading edge, creating a supersonic flow patch terminated by a shock on the suction surface. Rotating stall is triggered by growth of this separation, which is insensitive to leading edge shape. This creates a marked difference in sensitivity to damage at low- and high-speed operating points.

Space Shuttle Performance and Stability Implications with Wing Leading Edge Damage

2006 ◽  
Author(s):  
Travis Bryce ◽  
David Schmitt ◽  
Matthew Karmondy ◽  
Thomas Yechout
Keyword(s):  
Space Shuttle ◽  
Leading Edge ◽  
Edge Damage

Swimming of a waving plate

1961 ◽  
Vol 10 (3) ◽  
pp. 321-344 ◽  
Author(s):  
T. Yao-Tsu Wu
Keyword(s):  
General Theory ◽  
Phase Velocity ◽  
Wave Train ◽  
Leading Edge ◽  
Basic Mechanism ◽  
Simplified Model ◽  
Two Dimensional ◽  
Propulsive Efficiency ◽  
Fish Propulsion ◽  
Solid Plate

The purpose of this paper is to study the basic principle of fish propulsion. As a simplified model, the two-dimensional potential flow over a waving plate of finite chord is treated. The solid plate, assumed to be flexible and thin, is capable of performing the motion which consists of a progressing wave of given wavelength and phase velocity along the chord, the envelope of the wave train being an arbitrary function of the distance from the leading edge. The problem is solved by applying the general theory for oscillating deformable airfoils. The thrust, power required, and the energy imparted to the wake are calculated, and the propulsive efficiency is also evaluated. As a numerical example, the waving motion with linearly varying amplitude is carried out in detail. Finally, the basic mechanism of swimming is elucidated by applying the principle of action and reaction.

scholarly journals Machine Learning-Aided Assessment of Wind Turbine Energy Losses due to Blade Leading Edge Damage

2019 ◽  
Author(s):  
Anna Cavazzini ◽  
Edmondo Minisci ◽  
M. Sergio Campobasso
Keyword(s):  
Machine Learning ◽  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Wind Turbine ◽  
Energy Production ◽  
Leading Edge ◽  
Surface Damage ◽  
Energy Losses ◽  
Edge Damage ◽  
Blade Leading Edge

Abstract Estimating reliably and rapidly the losses of wind turbine annual energy production due to blade surface damage is essential for optimizing maintenance planning and, in the frequent case of leading edge erosion, assessing the need for protective coatings. These requirements prompted the development of the prototype system presented herein, using machine learning, wind turbine engineering codes and computational fluid dynamics to estimate wind turbine annual energy production losses due to blade leading edge damage. The power curve of a turbine with nominal or damaged blade surfaces is determined respectively with the open-source FAST and AeroDyn codes of the National Renewable Energy Laboratory, both using the blade element momentum theory for turbine aerodynamics. The loss prediction system is designed to map a given three-dimensional geometry of a damaged blade onto a damaged airfoil database, which, in this study, consists of 2700+ airfoil geometries, each analyzed with Navier-Stokes computational fluid dynamics over the working range of angles of attack. To avoid the need for lengthy aerodynamic analyses to assess losses due to damages monitored during turbine operation, the airfoil force data of a damaged turbine required by AeroDyn are rapidly obtained using a machine learning method trained using the pre-existing airfoil database. Presented results focus on the analysis of a utility-scale offshore wind turbine and demonstrate that realistic estimates of the annual energy production loss due to leading edge surface damage can be obtained in just a few seconds using a standard desktop computer, highlighting the viability and the industrial impact of this new technology for wind farm energy losses due to blade erosion.

scholarly journals Influence of aircraft engine compressor blades leading edge damage on their fatigue strength

Mechanik ◽  
2018 ◽  
Vol 91 (3) ◽  
pp. 205-209
Author(s):  
Wojciech Obrocki ◽  
Amadeusz Setkowicz ◽  
Maciej Masłyk ◽  
Jan Sieniawski
Keyword(s):  
Fatigue Strength ◽  
Leading Edge ◽  
Fatigue Cracking ◽  
Aircraft Engine ◽  
Fatigue Tests ◽  
Compressor Blade ◽  
Compressor Blades ◽  
Fluorescent Method ◽  
Engine Compressor ◽  
Edge Damage

Article presents the research results of aircraft compressor blade damage length and its position influence on fatigue strength under high number cycles conditions. The criteria for blade damage detection classification and test research methodology were developed. Designed and tested the instrumentation for compressor blades fatigue tests. Fluorescent method was used to determine the source of fatigue cracking initiation and its propagation direction during fatigue test.

Effect of Geometric Uncertainty on a One Stage Transonic Compressor of an Industrial Gas Turbine

2020 ◽  
Author(s):  
S. Venkatesh ◽  
K. Suzuki ◽  
M. Vahdati ◽  
L. Salles ◽  
Q. Rendu
Keyword(s):  
Leading Edge ◽  
Rotor Blades ◽  
Transonic Compressor ◽  
Manufacturing Tolerance ◽  
Geometric Uncertainty ◽  
Zigzag Pattern ◽  
Sinusoidal Pattern ◽  
And Performance ◽  
Edge Damage ◽  
Industrial Gas Turbine

Abstract The geometrical uncertainties can result in flow asymmetry around the annulus of compressor which in turn can detrimentally affect on the compressor stability and performance. Typically these uncertainties arise as a consequence of in-service degradation and/or manufacturing tolerance, both of which have been dealt with in this paper. The paper deals with effects of leading edge damage and tip gap on rotor blades. It was found that the chord-wise damage is more critical than radial damage. It was found that a zigzag pattern of arranging the damaged rotor blades (i.e. most damaged blades between two least damaged blades) would give the best possible performance and stability when performing maintenance and overhauling while a sinusoidal pattern of arrangement had the worst performance and stability. This behaviour of zigzag arrangement of random damaged blades is consonant with the behaviour of zigzag arrangement in random tip gaps. It is also shown in this work that the level of damage has a bigger impact on the compressor performance and stability than the number of damaged blades.

Numerical Modeling of the Effects of Leading-Edge Erosion and Trailing-Edge Damage on Wind Turbine Loads and Performance

2021 ◽  
Author(s):  
Francesco Papi ◽  
Lorenzo Cappugi ◽  
Sebastian Perez-Becker ◽  
Alessandro Bianchini
Keyword(s):  
Numerical Modeling ◽  
Wind Turbine ◽  
Leading Edge ◽  
Trailing Edge ◽  
And Performance ◽  
Edge Damage

scholarly journals Cavitation in Turbopumps—Part 1

1962 ◽  
Vol 84 (3) ◽  
pp. 326-338 ◽  
Author(s):  
L. B. Stripling ◽  
A. J. Acosta
Keyword(s):  
Leading Edge ◽  
Simplified Model ◽  
Flat Plates ◽  
Streamline Flow ◽  
Cavitation Process ◽  
Flow Through ◽  
Loss Coefficients ◽  
Blade Geometry

A free-streamline flow through a cascade of semi-infinite flat plates is taken as a simplified model of the cavitation process in a helical inducer pump. The length and thickness of the resulting cavity is determined as a function of blade geometry and cavitation parameter. Loss coefficients resulting from the cavitation are estimated and representative cavity shapes are calculated to aid in designing the leading edge shape of the blades.

Two Aspects of Cavitation Damage in the Incubation Zone: Scaling by Energy Considerations and Leading Edge Damage

1980 ◽  
Vol 102 (4) ◽  
pp. 481-485 ◽  
Author(s):  
D. R. Stinebring ◽  
J. William Holl ◽  
Roger E. A. Arndt
Keyword(s):  
Damage Zone ◽  
Pressure Rise ◽  
Leading Edge ◽  
Bubble Collapse ◽  
Test Model ◽  
Cavitation Damage ◽  
Pit Formation ◽  
Rate Versus ◽  
Wide Range ◽  
Edge Damage

This study focused on two aspects of the cavitation damage problem, namely an energy approach to the scaling of cavitation damage in the incubation zone and damage near the leading edge of a test model. The damage to the surface of the models was in the form of small indentations in which no material was removed. For a wide range of velocities namely 14.9 to 59.3 m/s the rate of pit formation per unit area in the maximum damage zone increased by the sixth power of velocity. Furthermore it is shown that the damage rate versus velocity data are in good agreement with three other investigations. The volumes of the pits were found to increase by the fifth power of velocity. A relationship between the volume of a pit and the cavitation bubble collapse energy absorbed was developed. The damage to the leading edge was felt to be due to the reentrant jet striking the leading edge of the cavity creating a short term pressure rise causing the collapse of any cavitation bubbles in this area.

Experimental control of swept-wing transition through base-flow modification by plasma actuators

2018 ◽  
Vol 844 ◽  
Author(s):  
Srikar Yadala ◽  
Marc T. Hehner ◽  
Jacopo Serpieri ◽  
Nicolas Benard ◽  
Philipp C. Dörr ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Cross Flow ◽  
Leading Edge ◽  
Base Flow ◽  
Plasma Actuators ◽  
Simplified Model ◽  
Swept Wing ◽  
Flow Component ◽  
Flow Modification ◽  
Barrier Discharge Plasma

Control of laminar-to-turbulent transition on a swept-wing is achieved by base-flow modification in an experimental framework, up to a chord Reynolds number of 2.5 million. This technique is based on the control strategy used in the numerical simulation by Dörr & Kloker (J. Phys. D: Appl. Phys., vol. 48, 2015b, 285205). A spanwise uniform body force is introduced using dielectric barrier discharge plasma actuators, to either force against or along the local cross-flow component of the boundary layer. The effect of forcing on the stability of the boundary layer is analysed using a simplified model proposed by Serpieri et al. (J. Fluid Mech., vol. 833, 2017, pp. 164–205). A minimal thickness plasma actuator is fabricated using spray-on techniques and positioned near the leading edge of the swept-wing, while infrared thermography is used to detect and quantify transition location. Results from both the simplified model and experiment indicate that forcing along the local cross-flow component promotes transition while forcing against successfully delays transition. This is the first experimental demonstration of swept-wing transition delay via base-flow modification using plasma actuators.

Sign in / Sign up

Export Citation Format

Share Document