scholarly journals Multi-fidelity Fluid-Structure Interaction Analysis of a Membrane Blade Concept in non-rotating, uniform flow condition

Author(s):  
Mehran Saeedi ◽  
Kai-Uwe Bletzinger ◽  
Roland Wüchner

Abstract. In order to study the aerodynamic performance of a semi-flexible membrane blade, Fluid-Structure Interaction simulations have been performed for a non-rotating blade under steady inflow condition. The studied concept blade has a length of about 5 m. It consists of a rigid mast at the leading edge, ribs along the blade, tensioned edge cables at the trailing edge and membranes forming upper and lower surface of the blade. Equilibrium shape of membrane structures in absence of external loading depends on the location of the supports and the pre-stresses in the membranes and the supporting edge cables. Form finding analysis is used to find the equilibrium shape. The exact form of a membrane structure at the service condition depends on the internal forces and also on the external loads which in turn depend on the actual shape. As a result, two-way coupled Fluid-Structure Interaction (FSI) analysis is necessary to study this class of structures. The fluid problem has been modeled using two different approaches which are the vortex panel method and the numerical solution of the Navier–Stokes equations. Nonlinear analysis of the structural problem is performed using the Finite Element Method. The goal of the current study is twofold: First, to make a comparison between the converged FSI results obtained from the two different methods to solve the fluid problem. This investigation is a prerequisite for the development of an efficient and accurate multi-fidelity simulation concept for different design stages of the flexible blade. The second goal is to study the aerodynamic performance of the membrane blade in terms of lift and drag coefficient as well as lift to drag ratio and to compare them with those of the equivalent conventional rigid blade. The blade configuration from the NASA-Ames Phase VI rotor is taken as the baseline rigid blade configuration. The studied membrane blade shows a higher lift curve slope and higher lift to drag ratio compared with the rigid blade.

2016 ◽  
Vol 1 (2) ◽  
pp. 255-269 ◽  
Author(s):  
Mehran Saeedi ◽  
Kai-Uwe Bletzinger ◽  
Roland Wüchner

Abstract. In order to study the aerodynamic performance of a semi-flexible membrane blade, fluid–structure interaction simulations have been performed for a non-rotating blade under steady inflow condition. The studied concept blade has a length of about 5 m. It consists of a rigid mast at the leading edge, ribs along the blade, tensioned edge cables at the trailing edge and membranes forming the upper and lower surface of the blade. Equilibrium shape of membrane structures in the absence of external loading depends on the location of the supports and the prestresses in the membranes and the supporting edge cables. Form-finding analysis is used to find the equilibrium shape. The exact form of a membrane structure for the service conditions depends on the internal forces and also on the external loads, which in turn depend on the actual shape. As a result, two-way coupled fluid–structure interaction (FSI) analysis is necessary to study this class of structures. The fluid problem has been modelled using two different approaches, which are the vortex panel method and the numerical solution of the Navier–Stokes equations. Nonlinear analysis of the structural problem is performed using the finite-element method. The goal of the current study is twofold: first, to make a comparison between the converged FSI results obtained from the two different methods to solve the fluid problem. This investigation is a prerequisite for the development of an efficient and accurate multi-fidelity simulation concept for different design stages of the flexible blade. The second goal is to study the aerodynamic performance of the membrane blade in terms of lift and drag coefficient as well as lift-to-drag ratio and to compare them with those of the equivalent conventional rigid blade. The blade configuration from the NASA-Ames Phase VI rotor is taken as the baseline rigid-blade configuration. The studied membrane blade shows a higher lift curve slope and higher lift-to-drag ratio compared with the rigid blade.


2021 ◽  
Vol 37 ◽  
pp. 216-229
Author(s):  
Yung Jeh Chu ◽  
Poo Balan Ganesan ◽  
Mohamad Azlin Ali

Abstract The dragonfly wings provide insights for designing an efficient biomimetic micro air vehicle (BMAV). In this regard, this study focuses on investigating the effect of the pterostigma weight loading and its spatial location on the forewings of dragonfly by using the fluid–structure interaction simulation. This study also investigates the effect of change in the wing elasticity and density on the wing performance. The forewing, which mimics the real dragonfly wing, is flat with a 47.5 mm span and a 0.4 mm thickness. The wing was set to cruise at 3 m/s with a constant flapping motion at a frequency of 25 Hz. This study shows that a small increase of pterostigma loading (11% of wing weight) at the tip of the wing significantly improves the lift to drag ratio, CL/CD, which has 129.16% increment in comparison with no loading. The lift to drag ratio depends on the pterostigma location, pterostigma loading, elastic modulus and density. The results of this study can be used as a reference in future BMAV wing optimization design.


Author(s):  
Lucia Sargentini ◽  
Benjamin Cariteau ◽  
Morena Angelucci

This paper is related to fluid-structure interaction analysis of sodium cooled fast reactors core (Na-FBR). Sudden liquid evacuation between assemblies could lead to overall core movements (flowering and compaction) causing variations of core reactivity. The comprehension of the structure behavior during the evacuation could improve the knowledge about some SCRAMs for negative reactivity occurred in PHÉNIX reactor and could contribute on the study of the dynamic behavior of a FBR core. An experimental facility (PISE-2c) is designed composed by a Poly-methyl methacrylate hexagonal rods (2D-plan similitude with PHÉNIX assembly) with a very thin gap between assemblies. Another experimental device (PISE-1a) is designed and composed by a single hexagonal rod for testing the dynamic characteristics. Different experiments are envisaged: free vibrations and oscillations during water injection. A phenomenological analysis is reported showing the flow behavior in the gap and the structure response. Also computational simulations are presented in this paper. An efficient numerical method is used to solve Navier-Stokes equations coupled with structure dynamic equation. The numerical method is verified by the comparison of analytic models and experiments.


Author(s):  
Sang-Bum Ma ◽  
Man-Woong Heo ◽  
Kwang-Yong Kim ◽  
Jaeho Choi

In this paper, a fluid-structure interaction (FSI) analysis was performed for a single-stage axial compressor with casing groove and tip injection using three-dimensional Reynolds-Averaged Navier-Stokes equations. The k-ε turbulence model and hexahedral grids system were used in the analysis. ANSYS solid 186 elements type was used to analyze the solid characteristic. In order to achieve robust stability of the transonic axial compressor, a casing groove was installed with tip injection on rotor tip region. FSI analysis was carried out to predict the deformation of the blades, and the results were compared to those of non-FSI analysis. Validation of the numerical results performed in comparison with experimental data, showed good agreements with experimental data for the adiabatic efficiency and total pressure ratio. It was found that deformation of blades affects the aerodynamic performance of the compressor to some extent. Stability of the axial compressor was enhanced by installing the casing groove with tip injection.


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