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Aerodynamic Forces – Subsonic Flight
Published in Rose G. Davies, Aerodynamics Principles for Air Transport Pilots, 2020
The wing with limited wing span and wing tip is called a finite wing. The airflow over a finite wing is three-dimensional. A finite wing is a real wing. Wings on existing aircraft are generally finite wings.
Flutter speed estimation using presented differential quadrature method formulation
Published in Engineering Applications of Computational Fluid Mechanics, 2019
Mohammad Ghalandari, Shahaboddin Shamshirband, Amir Mosavi, Kwok-wing Chau
In this section, the verifications of the introduced coupled formulation are carried out for two test cases. The first test case is a clamped free typical airfoil and the second one is a Goland shaped wing slender wing. Indeed, the airfoil is a finite wing with translational and torsional springs (Figure 1). Using unsteady Peters theory and also PP method (Haddadpour & Firouz-Abadi, 2009), the flutter speed estimation of typical section airfoil (Table 1) is evaluated (Figure 2).
Fluid-structure interaction simulation for performance prediction and design optimization of parafoils
Published in Engineering Applications of Computational Fluid Mechanics, 2023
Hong Zhu, Qinglin Sun, Jin Tao, Hao Sun, Zengqiang Chen, Xianyi Zeng, Damien Soulat
The flow behaviour on the upper surface in Figure 8 shows that streamlines around end-tip cells began to tilt from outside toward the center of the canopy. In contrast, the streamlines showed the opposite direction when flowing through the lower surface in Figure 9. This phenomenon resulted from the sharp-edge effects, which further created wake vortex cores at the trailing edge of the finite wing (Ghoreyshi et al., 2016).
A review of bridge scour mitigation measures using flow deflecting structures
Published in ISH Journal of Hydraulic Engineering, 2023
Vikalp Chauhan, Ellora Padhi, Rutuja Chavan, Gopal Das Singhal
The vortices that form around submerged vanes resemble the wake of an airplane’s wing. The ‘classical finite wing theory’ was initially used to the study of flow physics for submerged vanes by researchers at the IOWA College of Engineering (Odgaard and Kennedy 1983; Odgaard and Spoljaric 1986; Odgaard and Wang 1991a, 1991b), because the laws of flow dynamics can be addressed similarly to those of air dynamics as long as the flows are sub-critical. A submerged vane is a tiny hydraulic structure in the shape of a hydrofoil that causes pressure differences on its two surfaces due to changes in the approach flow velocity field. Based on this premise, pressure lowers gradually from the vane bottom to the tip level on the front side, while pressure rises from ground level to the vane tip on the back side of the vane. The pressure difference (dynamic) between the front and back sides of the vane is zero at the vane tips. Due to pressure equalization at the vane tips, the flow is driven upward on the front side and downward on the backside. Streamlines (Figure 5) that converge behind the vane have a discontinuous surface, and the flow on two sides is in opposite directions, causing a tip vortex and, as a result, helical motion downstream of the submerged vane, as seen in Figure 6. The trailing vortices are formed by the superposition of multiple horseshoe vortices that form when flow separation occurs at the vane’s trailing edge due to adverse pressure gradients. Each time the lift is changed, the following vortex is generated, equal in strength to the change in circulation, and the highest lift change at the vane tip results in a tip vortex (Odgaard and Kennedy 1983; Chauhan et al. 2022a). Submerged vanes are submerged for the majority of the time, and when the channel adjusts and stabilizes, they may get buried by sedimentation and naturally vegetated. Submerged vanes can be used to protect abutments/piers (Johnson et al. 2001), deepen the riverbed (Odgaard and Spoljaric 1986), and orient flow to allow a smooth transition through the bridge opening, depending on how they are placed. At the point where the vanes are installed, the vane-induced vortices form a vertical shear layer along the channel, reducing the flow velocity within the channel between the bank and the vanes, resulting in a weakening pressure gradient and a down-flow vortex upstream of the abutment, with a reduction in abutment scour expected as shown in Figure 7 (Bejestan et al. 2015).