Numerical Study of Two Flapping Airfoils in Tandem Configuration

Author(s):  
Timothy Broering ◽  
Yongsheng Lian ◽  
William Henshaw
2021 ◽  
Author(s):  
N. Hosseini ◽  
M. Tadjfar ◽  
A. Abba

Abstract For a tandem airfoil configuration, an airfoil is placed in the wake of an upstream airfoil. This interaction affects the aerodynamic forces of the airfoils, especially the downstream one. In the present study a tandem configuration consists of an upstream pitching airfoil and a downstream stationary airfoil is investigated. This study aims to investigate the role of reduced frequency and pitch amplitude of the upstream airfoil’s motion on lift and drag coefficients of two airfoils. These two parameters play an important role in the formation of vortices. The investigation is done for Selig-Donovan 7003 (SD7003) airfoils at low Reynolds number of 30,000 using a computational fluid dynamics. Incompressible URANS equations were employed for solving the flow field. It was found that for a fixed reduced frequency of 0.5 thrust is produced on the hindfoil for a part of cycle for different pitch amplitudes from light to deep stall while for a fixed pitch amplitude at different reduced frequencies high level of thrust or drag can be produced. The reason is related to the type and intensity of vortex-blade interaction.


2014 ◽  
Vol 28 (5) ◽  
pp. 378-386
Author(s):  
Jang-Pyo Hong ◽  
Bo Woo Nam ◽  
Kyoung-Won Yoon ◽  
Young-Sik Kim ◽  
Hong-Gun Sung

2017 ◽  
Vol 34 (5) ◽  
pp. 679-693 ◽  
Author(s):  
Y. J. Chu ◽  
W. T. Chong

AbstractThe increasing demands on renewable energy nowadays caused the development of marine current turbine industry. In order to improve the current design of marine current turbines, studies were conducted to analyse their hydrodynamic performances during operation. Since most of the time marine current turbines operate in arrays, it is important to understand the interactions between the turbines in order to design the optimum turbine farm. OpenFOAM® was used to simulate the turbine interactions of conventional and biomimetic marine current turbines in tandem configuration. The conventional marine current turbines were referred to Pinon et al. (2012) and Mycek et al. (2013) while the biomimetic marine current turbine was adopted from Chu (2016). The numerical simulations were conducted with turbines in different inter-device distances, A/D. The percentage differences of ‘‘efficiency’’, η between the IFREMER-LOMC and the biomimetic turbine case of inter-device distances, A/D = 4, 6, 8 and 10 are 14.3%, 6.4%, 3% and 1.92% respectively. The results show that the power produced by the biomimetic turbines in tandem is comparable with the IFREMER-LOMC turbines when A/D > 4. The biomimetic marine current turbines can be a fair choice due to their potential to have alternative fabrication method of their sheet-like turbine blades.


1998 ◽  
Vol 77 (2) ◽  
pp. 473-484 ◽  
Author(s):  
M. Sampoli, P. Benassi, R. Dell'Anna,

2020 ◽  
pp. 57-65
Author(s):  
Eusébio Conceiçã ◽  
João Gomes ◽  
Maria Manuela Lúcio ◽  
Jorge Raposo ◽  
Domingos Xavier Viegas ◽  
...  

This paper refers to a numerical study of the hypo-thermal behaviour of a pine tree in a forest fire environment. The pine tree thermal response numerical model is based on energy balance integral equations for the tree elements and mass balance integral equation for the water in the tree. The simulation performed considers the heat conduction through the tree elements, heat exchanges by convection between the external tree surfaces and the environment, heat exchanges by radiation between the flame and the external tree surfaces and water heat loss by evaporation from the tree to the environment. The virtual three-dimensional tree model has a height of 7.5 m and is constituted by 8863 cylindrical elements representative of its trunks, branches and leaves. The fire front has 10 m long and a 2 m high. The study was conducted taking into account that the pine tree is located 5, 10 or 15 m from the fire front. For these three analyzed distances, the numerical results obtained regarding to the distribution of the view factors, mean radiant temperature and surface temperatures of the pine tree are presented. As main conclusion, it can be stated that the values of the view factor, MRT and surface temperatures of the pine tree decrease with increasing distance from the pine tree in front of fire.


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