Flow Structure on Diamond and Lambda Planforms: Trailing-Edge Region

AIAA Journal ◽  
2005 ◽  
Vol 43 (7) ◽  
pp. 1490-1500 ◽  
Author(s):  
B. Yaniktepe ◽  
D. Rockwell
Keyword(s):  
Flow Structure ◽  
Edge Region ◽  
Trailing Edge

Two-Dimensional Experimental Investigation on the Effects of a Fowler Flap Gap and Overlap Size on the Wake Flow Field

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
David Demel ◽  
Mohsen Ferchichi ◽  
William D. E. Allan ◽  
Marouen Dghim
Keyword(s):  
Experimental Investigation ◽  
Flow Field ◽  
Angle Of Attack ◽  
Wake Flow ◽  
Two Dimensional ◽  
Edge Region ◽  
Suction Surface ◽  
Trailing Edge ◽  
Piv Measurements ◽  
Image Velocimetry

This work details an experimental investigation on the effects of the variation of flap gap and overlap sizes on the flow field in the wake of a wing-section equipped with a trailing edge Fowler flap. The airfoil was based on the NACA 0014-1.10 40/1.051 profile, and the flap was deployed with 40 deg deflection angle. Two-dimensional (2D) particle image velocimetry (PIV) measurements of the flow field in the vicinity of the main wing trailing edge and the flap region were performed for the optimal flap gap and overlap, as well as for flap gap and overlap increases of 2% and 4% chord beyond optimal, at angles of attack of 0 deg, 10 deg, and 12 deg. For all the configurations investigated, the flow over the flap was found to be fully stalled. At zero angle of attack, increasing the flap gap size was found to have minor effects on the flow field but increased flap overlap resulted in misalignment between the main wing boundary layer (BL) flow and the slot flow that forced the flow in the trailing edge region of the main wing to separate. When the angle of attack was increased to near stall conditions (at angle of attack of 12 deg), increasing the flap gap was found to energize and improve the flow in the trailing edge region of the main wing, whereas increased flap overlap further promoted flow separation on the main wing suction surface possibly steering the wing into stall.

Flow Structure and Turbulence in the Tip Region of a Turbomachine Rotor Blade

2007 ◽  
Author(s):  
Francesco Soranna ◽  
Yi-Chih Chow ◽  
Oguz Uzol ◽  
Joseph Katz
Keyword(s):  
Kinetic Energy ◽  
Turbulent Kinetic Energy ◽  
Flow Structure ◽  
Turbulent Diffusion ◽  
Rotor Blade ◽  
Trailing Edge ◽  
Left Hand ◽  
Tip Leakage ◽  
The Subject ◽  
Turbulence Production

The flow structure and turbulence in the tip region of a rotor blade operating downstream of a row of Inlet Guide Vanes (IGVs) are investigated experimentally in a refractive index matched facility that provides unobstructed view of the entire flow field. Stereo-PIV measurements are performed in closely spaced radial planes near the blade tip in a region extending from (slightly upstream of) the blade trailing edge to about 40% of the chord downstream of it. The data enable calculations of all the components of the phase-averaged velocity and vorticity vectors, as well as the strain rate, Reynolds stress, and turbulent diffusion tensors. Each rotor blade is confined between two tip-leakage vortices, a right hand vortex (RHV), generated by the subject blade and propagating along its right hand side, and a left hand vortex (LHV), generated by the previous blade in the same row and propagating along the left hand side of the subject blade. In addition, a trailing edge vortex (TEV) lays underneath the LHV and is subject to intense shearing/deformation by the LHV. RHV-induced radial gradients of radial phase-averaged velocity cause negative turbulence production, P, along the RHV-axis, and formation of a region of low P in the gap between the RHV and the blade suction surface. Trends of turbulent kinetic energy k and P within the RHV do not agree due to the effects of advection by the phase-averaged flow. To the left of the blade, shearing of the TEV by the LHV enhances turbulence production in the region between the two vortices and the rotor wake. Trends of turbulent kinetic energy and its production rate are in good agreement and peaks of k and P occur at the same location. As the TEV migrates away from the LHV, shearing effects become weaker and the dominant contributors to production are terms containing vortex-induced radial gradients of axial and radial velocities. Turbulent diffusion is a minor contributor to the evolution of turbulent kinetic energy in the tip region. It is also shown that the tip-leakage flow/vortex deteriorates the rotor blade performance, causing a ∼66% increase in shaft power input (per unit mass flow-rate) in the tip region in comparison with midspan.

scholarly journals Unsteady Flow Field Due to Nozzle Wake Interaction With the Rotor in an Axial Flow Turbine: Part II—Rotor Exit Flow Field

1997 ◽  
Vol 119 (2) ◽  
pp. 214-224 ◽  
Author(s):  
M. A. Zaccaria ◽  
B. Lakshminarayana
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Velocity Component ◽  
Axial Flow ◽  
Turbine Rotor ◽  
Edge Region ◽  
Trailing Edge ◽  
Rotor Wake ◽  
Cross Correlations ◽  
Far Wake

The two-dimensional steady and unsteady flow field at midspan in a turbine rotor has been investigated experimentally using an LDV with an emphasis on the interaction of the nozzle wake with the rotor flow field. The velocity measurements are decomposed into a time-averaged velocity, a periodic velocity component, and an unresolved velocity component. The results in the rotor passage were presented in Part I. The flow field downstream of the rotor is presented in this paper. The rotor wake profiles and their decay characteristics were analyzed. Correlations are presented that match the decay of the various wake properties. The rotor wake velocity defect decays rapidly in the trailing edge region, becoming less rapid in the near and far wake regions. The rotor wake semi-wake width increases rapidly in the trailing edge region and then grows more gradually in the near and far wake regions. The decay of the maximum unresolved unsteadiness and maximum unresolved velocity cross correlations is very rapid in the trailing edge region and this trend slows in the far wake region. In the trailing edge region, the maximum periodic velocity correlations are much larger than the maximum unresolved velocity correlations. But the periodic velocity correlations decay much faster than the unresolved velocity correlations. The interactions of the nozzle and rotor wakes are also studied. While the interaction of the nozzle wake with the rotor wake does not influence the decay rate of the various wake properties, it does change the magnitude of the properties. These and other results are presented in this paper.

A Simplified Method for Estimating the Properties of Thin Aerofoils Influenced by Jet

1960 ◽  
Vol 64 (593) ◽  
pp. 292-294
Author(s):  
Svetopolk Pivko
Keyword(s):  
Deflection Angle ◽  
Simple Procedure ◽  
Leading Edge ◽  
Inviscid Flow ◽  
Edge Region ◽  
Trailing Edge ◽  
First Case ◽  
Simplified Method ◽  
Attached Flow ◽  
Special Case

To predict the aerodynamical properties of a thin aerofoil, provided with a high velocity jet sheet in its trailing edge region, a simple procedure is proposed as follows. Two general separate cases concerned with the effect of a jet on an aerofoil are considered. In the first case, the jet is blown tangentially over the upper surface of the aerofoil, while in the second case, the jet is ejected at a deflection angle from the trailing edge. In this analysis a procedure which is similar to the classical Glauert treatment of thin aerofoils is applied.Consider first the special case of a thin aerofoil placed at zero incidence in a two-dimensional inviscid flow of velocity V0, with a jet emerging with an exit velocity V1 at distance x1 from the leading edge and blown tangentially over the upper surface of the aerofoil (Fig. 1). It is assumed that an effectively attached flow may be obtained.

Modification of Flow Structure and Sound Source by Hybrid Porous-serrated Trailing Edge

2020 ◽  
Vol 17 (3) ◽  
pp. 539-552
Author(s):  
Hanru Liu ◽  
Nanshu Chen ◽  
Yangang Wang ◽  
Zhijie Hu
Keyword(s):  
Flow Structure ◽  
Sound Source ◽  
Trailing Edge

Investigation of Post-Stall Aerodynamic Characteristics of Ventilated NASA LS (1)-0417 Airfoil

2019 ◽  
Vol 11 (4) ◽  
Author(s):  
M.R. Vimal ◽  
R. Puratchikanal ◽  
J. Dheenadhayalan ◽  
E. Karthikeyan ◽  
E. Ezhilan ◽  
...  
Keyword(s):  
Aerodynamic Characteristics ◽  
Vehicle Design ◽  
Computational Domain ◽  
Edge Region ◽  
Analysis Software ◽  
Trailing Edge ◽  
Design Software

NASA LS (1)-0417 is an airfoil profile widely used in vehicle design especially in aircrafts for subsonic and transonic speed regimes. Performance of the airfoil is mainly determined by stall aerodynamic characteristics during flight. Further increase in stalling angle of the airfoil, the engineers adopts a single or multiple flaps in the trailing edge region of the main airfoil. The present study deals with a new attempt to achieve the post-stall or increased lift characteristics of NASA LS (1)-0417 airfoil beyond the stalling angle. The airfoil’s surface parts are subjected to allow the air to flow freely over and into the airfoil with increase in lift. The modified airfoil is designed from the base airfoil using the commercial design software and imported to the computational domain with boundaries around the model and meshed properly for solving the problem using the analysis software. The aerodynamic characteristics are compared with the baseline NASA LS (1)-0417 airfoil.

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