Unsteady Forcing of A Post-Stall Flow Over N NACA0012 Airfoil By A Surface DBD actuator

2012 ◽  
Author(s):  
Audier Pierre ◽  
Dunpin Hong ◽  
Annie Leroy
Keyword(s):  
Naca0012 Airfoil

scholarly journals Plunging Airfoil: Reynolds Number and Angle of Attack Effects

Aerospace ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 216
Author(s):  
Emanuel A. R. Camacho ◽  
Fernando M. S. P. Neves ◽  
André R. R. Silva ◽  
Jorge M. M. Barata
Keyword(s):  
Reynolds Number ◽  
High Performance ◽  
Angle Of Attack ◽  
Systems Design ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Low Reynolds Numbers ◽  
Operational Conditions ◽  
Naca0012 Airfoil ◽  
The Mean

Natural flight has consistently been the wellspring of many creative minds, yet recreating the propulsive systems of natural flyers is quite hard and challenging. Regarding propulsive systems design, biomimetics offers a wide variety of solutions that can be applied at low Reynolds numbers, achieving high performance and maneuverability systems. The main goal of the current work is to computationally investigate the thrust-power intricacies while operating at different Reynolds numbers, reduced frequencies, nondimensional amplitudes, and mean angles of attack of the oscillatory motion of a NACA0012 airfoil. Simulations are performed utilizing a RANS (Reynolds Averaged Navier-Stokes) approach for a Reynolds number between 8.5×103 and 3.4×104, reduced frequencies within 1 and 5, and Strouhal numbers from 0.1 to 0.4. The influence of the mean angle-of-attack is also studied in the range of 0∘ to 10∘. The outcomes show ideal operational conditions for the diverse Reynolds numbers, and results regarding thrust-power correlations and the influence of the mean angle-of-attack on the aerodynamic coefficients and the propulsive efficiency are widely explored.

Dynamic Stall Simulation of Flow Over NACA0012 Airfoil at 1 Million Reynolds Number

2015 ◽  
Author(s):  
Venkata Ravishankar Kasibhotla ◽  
Danesh Tafti
Keyword(s):  
Reynolds Number ◽  
Flow Field ◽  
Lift Coefficient ◽  
Three Dimensional ◽  
Dynamic Stall ◽  
Sharp Drop ◽  
Airfoil Surface ◽  
Naca0012 Airfoil ◽  
Reduced Frequency ◽  
Edge Vortex

The paper is concerned with the prediction and analysis of dynamic stall of flow past a pitching NACA0012 airfoil at 1 million Reynolds number based on the chord length of the airfoil and at reduced frequency of 0.25 in a three dimensional flow field. The turbulence in the flow field is resolved using large eddy simulations with the dynamic Smagorinsky model at the sub grid scale. The development of dynamic stall vortex, shedding and reattachment as predicted by the present study are discussed in detail. This study has shown that the downstroke phase of the pitching motion is strongly three dimensional and is highly complex, whereas the flow is practically two dimensional during the upstroke. The lift coefficient agrees well with the measurements during the upstroke. However, there are differences during the downstroke. The computed lift coefficient undergoes a sharp drop during the start of the downstroke as the convected leading edge vortex moves away from the airfoil surface. This is followed by a recovery of the lift coefficient with the formation of a secondary trailing edge vortex. While these dynamics are clearly reflected in the predicted lift coefficient, the experimental evolution of lift during the downstroke maintains a fairly smooth and monotonic decrease in the lift coefficient with no lift recovery. The simulations also show that the reattachment process of the stalled airfoil is completed before the start of the upstroke in the subsequent cycle due to the high reduced frequency of the pitching cycle.

ANALYSIS OF A HETEROGENEOUS DOMAIN DECOMPOSITION FOR COMPRESSIBLE VISCOUS FLOW

2001 ◽  
Vol 11 (04) ◽  
pp. 565-599 ◽  
Author(s):  
CRISTIAN A. COCLICI ◽  
WOLFGANG L. WENDLAND
Keyword(s):  
Domain Decomposition ◽  
Stokes Equations ◽  
Domain Decomposition Method ◽  
Near Field ◽  
Outer Region ◽  
Navier Stokes ◽  
Far Field ◽  
Computational Domain ◽  
Linearized Euler Equations ◽  
Naca0012 Airfoil

We analyze a nonoverlapping domain decomposition method for the treatment of two-dimensional compressible viscous flows around airfoils. Since at some distance to the given profile the inertial forces are strongly dominant, there the viscosity effects are neglected and the flow is assumed to be inviscid. Accordingly, we consider a decomposition of the original flow field into a bounded computational domain (near field) and a complementary outer region (far field). The compressible Navier–Stokes equations are used close to the profile and are coupled with the linearized Euler equations in the far field by appropriate transmission conditions, according to the physical properties and the mathematical type of the corresponding partial differential equations. We present some results of flow around the NACA0012 airfoil and develop an a posteriori analysis of the approximate solution, showing that conservation of mass, momentum and energy are asymptotically attained with the linear model in the far field.

Wake-Airfoil Interaction as Broadband Noise Source: A Large-Eddy Simulation Study

2005 ◽  
Vol 4 (1-2) ◽  
pp. 93-115 ◽  
Author(s):  
Jérôme Boudet ◽  
Nathalie Grosjean ◽  
Marc C. Jacob
Keyword(s):  
Large Eddy Simulation ◽  
Particle Image ◽  
Broadband Noise ◽  
Far Field ◽  
Acoustic Analogy ◽  
Eddy Simulation ◽  
Naca0012 Airfoil ◽  
Image Velocimetry ◽  
Large Eddy ◽  
Proper Orthogonal

A large-eddy simulation is carried out on a rod-airfoil configuration and compared to an accompanying experiment as well as to a RANS computation. A NACA0012 airfoil (chord c = 0.1 m) is located one chord downstream of a circular rod (diameter d = c/10, Red = 48 000). The computed interaction of the resulting sub-critical vortex street with the airfoil is assessed using averaged quantities, aerodynamic spectra and proper orthogonal decomposition (POD) of the instantaneous flow fields. Snapshots of the flow field are compared to particle image velocimetry (PIV) data. The acoustic far field is predicted using the Ffowcs Williams & Hawkings acoustic analogy, and compared to the experimental far field spectra. The large-eddy simulation is shown to accurately represent the deterministic pattern of the vortex shedding that is described by POD modes 1 & 2 and the resulting tonal noise also compares favourably to measurements. Furthermore higher order POD modes that are found in the PIV data are well predicted by the computation. The broadband content of the aerodynamic and the acoustic fields is consequently well predicted over a large range of frequencies ([0 kHz; 10 kHz]).

Stability of the Low Reynolds Number Compressible Flow Past a NACA0012 Airfoil

AIAA Journal ◽  
2021 ◽  
pp. 1-15
Author(s):  
Laura Victoria Rolandi ◽  
Thierry Jardin ◽  
Jérôme Fontane ◽  
Jérémie Gressier ◽  
Laurent Joly
Keyword(s):  
Reynolds Number ◽  
Compressible Flow ◽  
Low Reynolds Number ◽  
Naca0012 Airfoil ◽  
Flow Past ◽  
Low Reynolds

Numerical investigation of an anti-icing method on airfoil based on the NSDBD plasma actuator

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Junjie Niu ◽  
Weimin Sang ◽  
Feng Zhou ◽  
Dong Li
Keyword(s):  
Phenomenological Model ◽  
Stokes Equations ◽  
Pulse Repetition Frequency ◽  
Leading Edge ◽  
Pulse Frequency ◽  
Plasma Actuator ◽  
Navier Stokes ◽  
Peak Voltage ◽  
Content Type ◽  
Naca0012 Airfoil

Purpose This paper aims to investigate the anti-icing performance of the nanosecond dielectric barrier discharge (NSDBD) plasma actuator. Design/methodology/approach With the Lagrangian approach and the Messinger model, two different ice shapes known as rime and glaze icing are predicted. The air heating in the boundary layer over a flat plate has been simulated using a phenomenological model of the NSDBD plasma. The NSDBD plasma actuators are planted in the leading edge anti-icing area of NACA0012 airfoil. Combining the unsteady Reynolds-averaged Navier–Stokes equations and the phenomenological model, the flow field around the airfoil is simulated and the effects of the peak voltage, the pulse repetition frequency and the direction arrangement of the NSDBD on anti-icing performance are numerically investigated, respectively. Findings The agreement between the numerical results and the experimental data indicates that the present method is accurate. The results show that there is hot air covering the anti-icing area. The increase of the peak voltage and pulse frequency improves the anti-icing performance, and the direction arrangement of NSDBD also influences the anti-icing performance. Originality/value A numerical strategy is developed combining the icing algorithm with the phenomenological model. The effects of three parameters of NSDBD on anti-icing performance are discussed. The predicted results show that the anti-icing method is effective and may be helpful for the design of the anti-icing system of the unmanned aerial vehicle.

Comparison of Two Active Flow Control Mechanisms of Pure Blowing and Pure Suction on a Pitching NACA0012 Airfoil at Reynolds Number of 1 × 106

2018 ◽  
Author(s):  
Ehsan Asgari ◽  
Mehran Tadjfar
Keyword(s):  
Reynolds Number ◽  
Flow Control ◽  
Active Flow Control ◽  
Hysteresis Loops ◽  
Leading Edge ◽  
Control Mechanisms ◽  
Airfoil Surface ◽  
Naca0012 Airfoil ◽  
Maximum Angle ◽  
Active Flow

In this study, we have applied and compared two active flow control (AFC) mechanisms on a pitching NACA0012 airfoil at Reynolds number of 1 × 106 using 2-D computational fluid dynamics (CFD). These mechanisms are continuous blowing and suction which are applied separately on the airfoil which pitches around its quarter-chord in a sinusoidal motion. The location for suction and blowing was determined in our previous study based on the formation of a counter clock-wise vortex near the leading-edge. In our current study, we have compared the effectiveness of pure blowing and pure suction in suppressing the dynamic stall vortex (DSV) which is the main contributor to the drag increase, particularly near the maximum angle of attack (AOA) and in early downstroke motion. The blowing/suction slot is considered as a dent on the airfoil surface which enables the AFC to perform in a tangential manner. This configuration would allow blowing jet to penetrate further downstream and was shown to be more effective compared to a cross-flow orientation. We have compared the two aforementioned mechanisms in terms of hysteresis loops of lift and drag coefficients and have demonstrated the dynamics of flow in controlled and uncontrolled situations.

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