Projecte llegit
Títol: Hysteretical behaviour of a NACA 0012 airfoil at ultralow Reynolds upon variation of the angle of attack
Estudiants que han llegit aquest projecte:
BERGILLO CORTES, JORDI (data lectura: 30-10-2017)- Cerca aquest projecte a Bibliotècnica
BERGILLO CORTES, JORDI (data lectura: 30-10-2017)Director/a: MELLIBOVSKY ELSTEIN, FERNANDO PABLO
Departament: FIS
Títol: Hysteretical behaviour of a NACA 0012 airfoil at ultralow Reynolds upon variation of the angle of attack
Data inici oferta: 04-02-2017 Data finalització oferta: 04-10-2017
Estudis d'assignació del projecte:
- GR ENG SIST AEROESP
| Tipus: Individual | |
| Lloc de realització: EETAC | |
| Paraules clau: | |
| Aerodynamical hysteresis, Edge tracking method, Direct Navier Stokes, Airfoil, Nektar++ | |
| Descripció del contingut i pla d'activitats: | |
| Boundary layer separation results in poor aerodynamic performance of wings at high angles of attack. Active flow control aims at delaying (or even suppressing) separation. This can be achieved by employing periodic perturbation with pulsating jets generated with fluidic oscillators. This project will analyse the effects of pulsating/sweeping jets on the aerodynamic performance of the NACA0012 airfoil at the ultralow Reynolds number regime.
The work plan will consist of the following activities 1) Literature review on boundary layer separation, airfoil performances at ultra low Reynolds number and active flow control with pulsating/sweeping jets. 2) Choice of a Reynolds regime and angle of attack with well documented uncontrolled performances. Meshing, spectral-elements computation setup and convergence analysis for domain and mesh optimisation. 3) 2D airfoil baseline simulation for collection of vortex-shedding statistics. 4) Parametric analyisis of 2D fluidic actuation varying, jet location, frequency and amplitude. 5) 3D baseline simulation for performance assessment. 6) Implementation of the 2D optimal control strategy on the 3D configuration. 7) Conclusions. |
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| Overview (resum en anglès): | |
| Reynolds's low numbers studies are necessary to understand the physics surrounding aerodynamics in larger Reynolds numbers where the phenomena they appear are becoming increasingly complex and it is very necessary to use mathematical models to model what is happening. Our scenario is described by a Reynolds of 5300 and for this configuration we find a case of aerodynamic hysteresis around the 7º angle of attack. We find the coexistence of two solutions for these values and we want to show that there is a third unstable solution that connects the other two. In order to do this we will have to use computational fluid dynamics in order to find a solution to the Navier-Stokes equations that govern our case and to be able to do the appropriate simulations. The method that we will use to determine the existence of this unstable solution is Edge Tracking. This method will allow us to determine what are the initial conditions necessary to fall to the unstable solution. The more accurate we are achieving with each iteration, the more time we will be able to be above the boundary of the unstable region before it is attracted to one of the stables. In addition, we will study the different solutions obtained and compare them with others in order to make a good description. We will compare the aerodynamic forces, but also two phenomena such as the detachment of the boundary layer or the vortex shedding, making the latter a frequency analysis using the Fourier transform. Finally, we have succeeded in demonstrating the existence of the unstable region for our study scenario.
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