Thrust Generation by Simultaneous Flapping Airfoil in Tandem Configuration

2006 ◽  
Author(s):  
Kwanjung Yee ◽  
Wandon Joo ◽  
Jihoon Jeong ◽  
Dong-ho Lee
Keyword(s):  
Tandem Configuration ◽  
Thrust Generation ◽  
Flapping Airfoil

Study of Aerodynamic Interactions of Dual Flapping Airfoils in Tandem Configurations

2012 ◽  
Vol 160 ◽  
pp. 301-306
Author(s):  
Bao Li Zhu ◽  
Hui Pen Wu ◽  
Tian Hang Xiao
Keyword(s):  
Viscous Flow ◽  
Great Influence ◽  
Aerodynamic Performance ◽  
Navier Stokes ◽  
Propulsive Efficiency ◽  
Motion Models ◽  
Hybrid Meshes ◽  
Thrust Generation ◽  
Unsteady Viscous Flow ◽  
Flapping Airfoil

The unsteady viscous flow fields of dual flapping airfoils in tandem configurations are simulated by a Navier-Stokes Solver based on dynamic deformable hybrid meshes. Aerodynamic interactions of three motion models are studied including flapping fore airfoil with fixed aft airfoil, two airfoils flapping in phase and out-of-phase. The results indicate that the aft airfoil in the wake of the flapping fore airfoil has great influence on the aerodynamic performance. When the fore airfoil flaps with a fixed aft airfoil, the thrust generation and thrust propulsive efficiency were enhanced by 65% and 44% respectively, compared to that of single flapping airfoil. When the two airfoils stoke in phase, the thrust generation is twice over that of single flapping airfoil. However the out-of-phase stroking has relatively much lower thrust.

BLOCKAGE RATIO INFLUENCE ON FLOW OVER CYLINDERS WITH TANDEM CONFIGURATION L/D = 1.26

2020 ◽  
Author(s):  
Roberta Fatima Neumeister ◽  
Adriane Prisco Petry ◽  
Sergio Viçosa Möller
Keyword(s):  
Blockage Ratio ◽  
Tandem Configuration

Bistatic SAR Data Focusing Using a Frequency Scaling Algorithm Based on an Analytical Spectrum in Tandem Configuration

2011 ◽  
Vol 33 (6) ◽  
pp. 1447-1452
Author(s):  
Shi-chao Chen ◽  
Qi-song Wu ◽  
Ming Liu ◽  
Meng-dao Xing ◽  
Zheng Bao
Keyword(s):  
Frequency Scaling ◽  
Tandem Configuration ◽  
Bistatic Sar ◽  
Sar Data

Thrust generation by a heaving flexible foil: Resonance, nonlinearities, and optimality

2016 ◽  
Vol 28 (1) ◽  
pp. 011903 ◽  
Author(s):  
Florine Paraz ◽  
Lionel Schouveiler ◽  
Christophe Eloy
Keyword(s):  
Thrust Generation

scholarly journals Numerical Simulation and Hydrodynamic Performance Predicting of 2 Two-Dimensional Hydrofoils in Tandem Configuration

2021 ◽  
Vol 9 (5) ◽  
pp. 462
Author(s):  
Yuchen Shang ◽  
Juan J. Horrillo
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Resource Constraints ◽  
Lift Coefficient ◽  
Parametric Method ◽  
Experimental Results ◽  
Hydrodynamic Performance ◽  
Tandem Configuration ◽  
Artificial Neural Network Ann ◽  
Naca 0012

In this study we investigated the performance of NACA 0012 hydrofoils aligned in tandem using parametric method and Neural Networks. We use the 2D viscous numerical model (STAR-CCM+) to simulate the hydrofoil system. To validate the numerical model, we modeled a single NACA 0012 configuration and compared it to experimental results. Results are found in concordance with the published experimental results. Then two NACA 0012 hydrofoils in tandem configuration were studied in relation to 788 combinations of the following parameters: spacing between two hydrofoils, angle of attack (AOA) of upstream hydrofoil and AOA of downstream hydrofoil. The effects exerted by these three parameters on the hydrodynamic coefficients Lift coefficient (CL), Drag Coefficient (CD) and Lift-Drag Ratio (LDR), are consistent with the behavior of the system. To establish a control system for the hydrofoil craft, a timely analysis of the hydrodynamic system is needed due to the computational resource constraints, analysis of a large combination and time consuming of the three parameters established. To provide a broader and faster way to predict the hydrodynamic performance of two hydrofoils in tandem configuration, an optimal artificial neural network (ANN) was trained using the large combination of three parameters generated from the numerical simulations. Regression analysis of the output of ANN was performed, and the results are consistent with numerical simulation with a correlation coefficient greater than 99.99%. The optimized spacing of 6.6c are suggested where the system has the lowest CD while obtaining the highest CL and LDR. The formula of the ANN was then presented, providing a reliable predicting method of hydrofoils in tandem configuration.

scholarly journals Numerical simulation of flapping airfoil with alula

2020 ◽  
Vol 12 ◽  
pp. 175682932097798
Author(s):  
Han Bao ◽  
Wenqing Yang ◽  
Dongfu Ma ◽  
Wenping Song ◽  
Bifeng Song
Keyword(s):  
Aerodynamic Force ◽  
Angle Of Attack ◽  
Leading Edge ◽  
Aerodynamic Performance ◽  
Geometric Parameters ◽  
Flight Performance ◽  
Relative Angle ◽  
Vertical Distance ◽  
Unsteady Effect ◽  
Flapping Airfoil

Bionic micro aerial vehicles have become popular because of their high thrust efficiency and deceptive appearances. Leading edge or trailing edge devices (such as slots or flaps) are often used to improve the flight performance. Birds in nature also have leading-edge devices, known as the alula that can improve their flight performance at large angles of attack. In the present study, the aerodynamic performance of a flapping airfoil with alula is numerically simulated to illustrate the effects of different alula geometric parameters. Different alula relative angles of attack β (the angle between the chord line of the alula and that of the main airfoil) and vertical distances h between the alula and the main airfoil are simulated at pre-stall and post-stall conditions. Results show that at pre-stall condition, the lift increases with the relative angle of attack and the vertical distance, but the aerodynamic performance is degraded in the presence of alula compared with no alula, whereas at post-stall condition, the alula greatly enhances the lift. However, there seems to be an optimal relative angle of attack for the maximum lift enhancement at a fixed vertical distance considering the unsteady effect, which may indicate birds can adjust the alula twisting at different spanwise positions to achieve the best flight performance. Different alula geometric parameters may affect the aerodynamic force by modifying the pressure distribution along the airfoil. The results are instructive for design of flapping-wing bionic unmanned air vehicles.

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