Numerical Analysis of Flutter Instability in Simplified Blade Cascade

Abstract

Abstract. In this paper the occurrence of flutter in a simplified blade cascade is analysed. The simplified blade cascade is formed by three flat plates, which perform a kinematic harmonic motion, each with a different inter-blade phase angle. The inter-blade phase angles are chosen in order for travelling wave mode of vibration to be present. The aim of the simulations is to determine the aerodynamic damping coefficients caused by the aerodynamic forces acting on the flat plates, which show whether flutter occurs. The non-linear system of Favre-averaged NavierStokes equations in ALE formulation completed by the Spalart-Allmaras turbulence model was chosen as the mathematical model. The simulations were performed using the developed inhouse CFD software based on the discontinuous Galerkin method, which offers high order of accuracy.

Numerical and experimental study of fluid flow in simplified blade cascade with prescribed harmonic motion

“…σ , c w2 = 0.3, c w3 = 2.0, c v1 = 7.1, The discretization of the mathematical model in ALE formulation using the discontinuous Galerkin method [7], [8] is described in previous works [4] and [9] in detail. Here, a simple algorithm for mesh deformation is also described.…”

“…The mentioned mathematical model is incorporated in the developed inhouse numerical software called FlowPro. The software is validated on an inviscid compressible unsteady fluid flow around oscillating NACA0012 airfoil for a free stream Mach number M ∞ = 0.755 [4]. The instantaneous motion of the airfoil is given as a function of time…”

“…In our previous work [4] we used the travelling wave mode approach for the numerical modelling of the unsteady flow in the simplified blade cascade formed by three flat plates. We prescribed a harmonic motion for all three flat plates in the cascade such that their mutual movement e-mail: jvimmr@kme.zcu.cz e-mail: pesek@it.cas.cz produces a travelling wave.…”

On the effect of moving blade grid on the flow field characteristics

“…[4] revealed that the flow is mainly affected by the changing wing angle and the effect of displacement is rather small. This experimental work is closely linked to the project dealing with aeroelastic couplings and dynamic behaviour of rotational periodic bodies [5,6]. Vimmr et al [5] carried out a numerical study which uses a simplified model of blade cascade (3 airfoils) which perform harmonic motion and with individual inter-blade phase angle.…”

“…This experimental work is closely linked to the project dealing with aeroelastic couplings and dynamic behaviour of rotational periodic bodies [5,6]. Vimmr et al [5] carried out a numerical study which uses a simplified model of blade cascade (3 airfoils) which perform harmonic motion and with individual inter-blade phase angle. This angle is chosen in order to set a travelling wave mode of vibration which is present in the rotational solid bodies.…”