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Analysis of Speed, Yaw Angle and Angle of Attack on a Vehicle using Wind Tunnel Testing
Published in P. C. Thomas, Vishal John Mathai, Geevarghese Titus, Emerging Technologies for Sustainability, 2020
Force: For the baseline model without wing the force coefficient remains constant.The drag coefficient increases with increase in the wing angle of attack. The lift coefficient reduces with increase in the wing angle of attack. There are no considerable changes in the side coefficient with increasing angle of attack. The wings here prevent the separation of flow downstream as a result higher downforce is generated with lower lift induced drag. [2]. In the graph for the negative inclination angles that produce undesirable effects in particular, an increase in both lift and drag coefficients. According to the trend in this scenario, further increase in the wing angle will increase the drag coefficient which is undesirable for passenger cars as they might stringent emission legislations of CO2. In no wing condition, the downforce on the front axle is much higher than the rear axle so it disturbs the car’s balance by increase in the yaw angle of rear tyres and vice versa. The presence of wings reduces yaw angle of rear tyre when cornering or during wind gusts. Higher aerodynamic forces are necessary for cornering thus, higher wing angle is needed. [5]. For higher angles, the boundary layer is formed near the surface and the lift of this boundary layer may create an effective shape that is different from the physical shape.
Principles and Applications of Plasma Actuators
Published in Ranjan Vepa, Electric Aircraft Dynamics, 2020
A Gurney flap, illustrated in Figure 9.7, is small rectangular flap-like device located on the pressure side of the airfoil, towards the trailing edge, and having a width of around 1–3% of the chord. The Gurney flap increases lift produced by the airfoil, with only a small increase in drag, making it an effective, low-maintenance, high-lifting device, which was introduced in the early 70s in the racing industry to increase the downforce on the cars.
The Power of Shape
Published in Patrick Hossay, Automotive Innovation, 2019
Perhaps the most advanced example of linking active upper and lower, front and rear aerodynamic features is the Lamborghini Active Aerodynamics (or Aerodynamica Lamborghini Attiva, ALA) system in the Performante (Image 8.24). An active front spoiler can function as a normal splitter, dividing front airflow either through the engine bay or under the car. This enhances cooling and can produce useful front-end downforce, as discussed, at the cost of increased front-end drag. However, a flap valve in this splitter can define an alternative route for airflow, opening a channel that sends front flow under the car. The escape of front-end pressure reduces drag but at the expense of downforce. The active rear wing is enhanced with a similar mechanism. Under normal conditions, clean air travels over the rear airfoil producing downforce and some associated drag. However, active shutter valves can direct ram airflow onto the rear surface of the wing, destroying the downforce and reducing drag. Varying a rear wing’s angle of attack is, of course, another way of achieving control; but the ALA option has the advantage of simplicity and light weight, avoiding the heavy hydraulics used in most active rear spoilers.
Modeling and performance evaluation of sustainable arresting gear energy recovery system for commercial aircraft
Published in International Journal of Green Energy, 2023
Jakub Deja, Iman Dayyani, Martin Skote
To validate the arresting gear concept, a simulation was initialized with parameters given in Section 3 and the set of differential equations was analyzed in time domain using MATLAB/Simulink software. The idealized dynamic model assumes (a) a rigid airframe with the weightless rotational components, (b) a rigid winding drum, (c) an arresting cable acting as a spring, (d) idealized generator dynamics, (e) six degrees of freedom, (f) degrees of freedom consisting of aircraft linear motion and five subsystems angular motion, (g) an aircraft aligned perfectly with centreline, (h) aerodynamics accounting to drag only (neither lift nor downforce) and (i) International Standard Atmosphere (ISA) flight condition at sea level. Figure 4 presents The top-level simulation logic flowchart.
Vertical trajectory planning: an optimal control approach for active suspension systems in autonomous vehicles
Published in Vehicle System Dynamics, 2022
Model accuracy depends on the estimation of each variable in the equations of motion. Vehicle parameters can be determined either by measurement or estimated online. Lateral and longitudinal forces are estimated from the intended vehicle trajectory and driving resistance forces. Latter considers slope, air resistance and inertial forces. Lastly suspension force is the sum of all acting vertical forces of suspension elements, including spring () as well as the forces, which are generated by the axle (/). It also includes aerodynamic lift and downforce. As the damper is used as actuator in this case, damping force is included in the actuator force . If a different actuator is used, damper force must also be included in . The same applies to an anti-roll bar if one is installed.
Modelling minimum-time manoeuvering with global optimisation of local receding horizon control
Published in Vehicle System Dynamics, 2018
Jeffery Ryan Anderson, Beshah Ayalew
A simple aerodynamic model is used to capture the speed-dependent down force () and drag () quantities acting on the vehicle. These forces are applied to the vehicle centre of pressure shown in Figure 1. Other aerodynamic affects such as yaw and pitch are coupling are neglected for the purposes of this work. The aerodynamic forces are described by The constants , and are the downforce and drag coefficients, respectively. The vehicle's frontal area is denoted with A and the air density is denoted with ρ.