Wyniki wyszukiwania - BazTech

Ograniczanie wyników

2 2000

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Application of the coupled Euler / flight dynamics model into analysisof a rapid pull-up manoeuvre

Goraj Z., Iglewski T.

Research Bulletin / Warsaw University of Technology, Institute of Aeronautics and Applied Mechanics

2000

nr 10

113-120

The Eater flow model for in viscid, compressible gas and the aircraft flight dynamics model were coupled to analyse rapid pull-up manoeuvre. The Euler flow equations were used to obtain aerodynamic forces and moments acting on a simplified aircraft configuration, considered as a rigid body. The McCormack predictor-corrector scheme for a finite differences representation was used as a numerical method for solving the Euler flow equations. The second order artificial viscosity was introduced to improve convergence of the scheme. Far field boundary conditions in the Euler model were determined from the steady state conditions of in the horizontal flight. Aircraft components in the body frame of were computed having known the of attack of the aircraft and its speed. The air density and pressure correspond to the height. From the boundary condition on the wing surface it follows that local flow vector is tangent to the local surface. 225200 grid points in five connected structural grid blocks in computations. The flight dynamics equations of motion were used to describe the aiecraft dynamics. No additional aerodynamic derivatives were considered. Some dynamic phenomena and damping effects (including hysteresis) were taken into account. In the simulation process both models were used and coupled by means of the mutual data transfer process. Any change of flight conditions immediately influences on the flow. Initial conditions for the flight dynamics equations of motion were settled up coming from the solutionof the Euler flow model for several cases of stationary flow. Only symmetrical motion and symmetrical airflow were examined. This makes it possible to use a grid for half of the aircraft only. The influence of the horizontal tailplane and fuselage on the main wing flow was neglected. The results of simulation (including flight path history, surface loading, aerodynamic forces and moments) were compared to those of classical approach, obtained from pure flight dynamics equations of motion.

Zastosowanie modelu Eulera do wyznaczania kątów odchylenia strug za płatem

Iglewski T., Goraj Z.

Prace Instytutu Lotnictwa

2000

Nr 2 (161)

70-77

Zastosowano przestrzenne równania Eulera do modelowania ruchu płynu nielepkiego wokół izolowanego płata. Przedstawiono sposób rozwiązywania tych równań metodą różnic skończonych na niejednorodenj siatce otaczającej opływany obiekt. Zaprezentowano możliwość stosowania siatek wieloblokowych jako sposób opisu skomplikowanych geometrii. Przedstawiono metodę łączenia siatek wieloblokowych. Równania Eulera wykorzystano do wyznaczania kąta odchylenia strug w przestrzeni za płatem. Otrzymane wyniki dla różnych geometrii porównano z wynikami z innych źródeł: tablic inżynierskich, wzorów analitycznych i danych eksperymentalnych.

Three dimensional Euler equations in the conservative form were used to simulate flow field around separated wing. Finite-difference computation method, based on Mac Cormack technique for non-uniform, structured multiblock grig system is presented and applied to describe a wing of an arbitrary planform. This method was used to simulate downwash for several different wing configurations. Simulation results were compared to results from other sources as data sheets, analytical formulae and experimental data.