Sharp Transition in the Lift Force of a Fluid Flowing Past Nonsymmetrical Obstacles: Evidence for a Lift Crisis in the Drag Crisis Regime

Discontinuity of lift on a hydrofoil in reversed flow for tidal turbine application

“…Such a behavior may resemble an asymmetric scenario reported for the drag crisis transition of a circular cylinder, called the one-bubble state [35]. Moreover, the lift jump observed here could be related as well to the lift crisis phenomenon reported by Bot et al [36] on asymmetric bodies. For further work, it would be interesting to investigate how this spontaneous symmetry breaking appears when increasing the Reynolds number from a laminar flow, and to measure how the bistability range in angle of attack changes with Re, in order to characterize the related bifurcation.…”

Surface Patterns for Drag Modification in Volleyballs

“…The aerodynamic coefficients of the drag coefficient (C d ), the lift force coefficient (C l ) and the side force coefficient (C s ) were calculated as C d = 2D ρU 2 A , C l = 2L ρU 2 A and C s = 2S ρU 2 A , respectively. Here ρ is the density of air (ρ = 1.2 kg/m 3 ), A is the cross-sectional area of the volleyball (A = πd 2 /4 ≈ 0.0346 m 2 for the diameter of the volleyball d = 0.21 m [15]), and the D, L, and S quantities are the longitudinal, transverse and side components of the aerodynamic forces [6].…”

“…When a spherical ball moves through the air, a long tangle of swirling air trails behind it [1][2][3][4][5][6]. A turbulent flow causes to slow the ball down.…”

“…The aerodynamic lift and drag forces can make a volleyball swerve up or down and/or side to side: lift acts in a direction perpendicular to motion and drag acts to directly oppose motion [5]. Drag crisis is still a puzzling phenomenon in fluid mechanics [6].…”

Numerical simulations of the aerodynamic response of circular segments with different corner angles by means of 2D URANS. Impact of turbulence modeling approaches

“…This may also decelerate the flow over the rectilinear side of the Dsection. Further studies on shear layer instability (Singh & Mittal, 2005) and the interaction between shear layers would be required for this cross-section due to the lack of data for non-symmetrical geometries in the flow direction, as it has been highlighted by Bot, Rabaud, Thomas, Lombardi, and Lebret (2016). A similar peak has been described for circular cylinders in smooth flow in terms of C D in the work by Kwok (1986).…”