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Comparison of panel codes for aerodynamic analysis of airfoils
Bilčík, Adam ; Schoř, Pavel (referee) ; Popela, Robert (advisor)
Cieľom tejto práce bolo vytvorenie prehľadu v súčasnosti používaných implementácií panelových metód pre aerodynamické výpočty charakteristík 2D profilov. Základný popis princípu panelovej metódy, porovnanie jednotlivých implementácií a zhodnotenie ich možností (presnosť, aplikovateľnosť) na typické úlohy. V práci boli použité tri rôzne panelové programy: Xfoil, JavaFoil a XFLR5. Práca bola obohatená o meranie v aerodynamickom tuneli.
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Flutter methodology using reduced order aeroelastic model
Prasad, Chandra Shekhar ; Pešek, Luděk ; Šnábl, Pavel
The present research project is focused on development of fast and efficient numerical method based on reduced order aeroelastic method (ROAM) for modeling and analysis of \nclassical flutter in the low pressure (LP) stage steam turbine blade. Stability diagram such as aerodynamic damping (AD) of aeroelasticity of cascade of 3D turbine blades used as a prime \ncharacterization factor. In the calculation of the S-curve/AD, the problem of classical flutter formation associated with running waves is considered here. Running waves is simulated by \nthe inter-blade phase shift of the blades in the cascade. Panel method based boundary element flow solver is employed for calculation of unsteady aerodynamic forces. This method is good \ncompromise of speed and accuracy for the estimation of the stability of the blades on a classical flutter. One way loose coupling technique between PM based flow solver and the structural \nmodel. For the structural part modal model synthesis (MMS) method is adopted in the ROAM solver. MMS is adopted to further reduced the computational cost. The ROAM simulated AD \nand pressure distribution over blade is compared high fidelity CFD data on real blade geometry provided by Doosan Skoda Power s.r.o. Furthermore, the ROAM results are also compared \nwith experimentally obtained results on two different linear cascade. The ROAM model shows good agreement with linear cascade results, however, there is noticeable discrepancy with real blade CFD results.
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A hybrid boundary element based aeroelastic model for flexible wing.
Prasad, Chandra Shekhar ; Pešek, Luděk
The paper describes development of medium delity aeroelastic numerical model for fast aeroelastic analysis of the flexible aeronautical structures e.g. wings, rotor blades etc. The numerical model is developed particularly for the incompressible low subsonic flow regime application. For the flow field modeling boundary element based hybrid panel method flow solver with viscous-inviscid coupling strategy have been successfully developed and implemented here.The unsteady flow field is modeled using hybrid/modi ed panel method where, integral boundary layer theory (vis-cous part), surface panel method (potential flow inviscid part) and vortex particle method (separated shear layer modeling) are coupled together. The proposed model can simulate both attached and separated flow fields. The estimated aerodynamic lift coefficients and the pressure coefficient are compared with experimental results for static and dynamic stall flow conditions. Furthermore, the results from new aeroelastic model will be compared with classical CFD-CSD based aeroelastic models for efficiency and accuracy check. The proposed methodology for the aeroelastic analysis of long exible aeronautical structure will provide researchers and engineers a fast, cost effective and efficient tool for aeroelastic analysis for different design at preliminary design stage where large numbers of design iteration are required within short time frame.
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Classical flutter analysis of low pressure steam turbine blade cascade using 3D boundary element method
Prasad, Chandra Shekhar ; Pešek, Luděk
In this paper study of aeroelastic stability in steam turbine rotor is carried out using boundary element method. A mesh free fluid\nsolver is developed for fast estimation of unsteady aerodynamic loading and to estimate the aerodynamic damping in 3D blade cascade. The aerodynamic damping is estimated in traveling wave mode. The unsteady incompressible flow field is modeled using 3D surface Panel method. The proposed methodology successfully estimates aerodynamic damping with acceptable accuracy the for the aeroelastic (classical \n flutter) analysis of 3D blade cascade. The simulated results are compared with experimental data. The simulated aerodynamic damping shows good agreement with\nexperimental results. The present methodology shows significant reduction in computational time over computational fluid dynamic solvers.
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Comparison of panel codes for aerodynamic analysis of airfoils
Bilčík, Adam ; Schoř, Pavel (referee) ; Popela, Robert (advisor)
Cieľom tejto práce bolo vytvorenie prehľadu v súčasnosti používaných implementácií panelových metód pre aerodynamické výpočty charakteristík 2D profilov. Základný popis princípu panelovej metódy, porovnanie jednotlivých implementácií a zhodnotenie ich možností (presnosť, aplikovateľnosť) na typické úlohy. V práci boli použité tri rôzne panelové programy: Xfoil, JavaFoil a XFLR5. Práca bola obohatená o meranie v aerodynamickom tuneli.
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