Air drag coefficient of textile-covered elastic cylinders – preliminary aerodynamic studies

This paper presents preliminary experimental results on the influence on the aerodynamic drag of a cylinder from the cylinder type (i.e., rigid or soft) and its textile surface. Both a rigid cylinder and a soft-body cylinder, with a gelatin layer, each with five different textile surfaces were measured in the wind tunnel using force measurement technology. The drag coefficient was determined for several Reynolds numbers. The study shows that the elasticity of a cylinder has a significant influence on the drag force and the airflow type. However, the influence of the soft-body cylinder depends on the respective fabric. With the given measurements, no exact statements can yet be made to quantify the influence. This influence must be studied independently and in conjunction with the textile surface in order to gain understanding of the overall system of airflow, textile and elastic body.

Design and Wheel Torque Performance Test of the Electric Racing Car Concept E-Falco

To reduce the use of fossil fuels in vehicles and reduce exhaust emissions, it is necessary to use electric vehicle technology. Solidworks software is used in designing and manufacturing an electric car and a simulation is carried out using CFD (Computation Fluid Dynamic) software to determine the strength of the frame structure and air drag when the electric car is running. The performance test of the motor by using the dyno test to determine the acceleration time, power, and torque of the motor. The results of the simulation show that at a speed of 10 km/h the air drag is 6.24 N, a speed of 20 km/h is 24.64 N, and a speed of 40 km/h is 93.92 N. The results of the dyno test shows that the acceleration time with full acceleration from a speed of 0-70 km/h is 13.63 seconds, the maximum power output by the motor is 14.17 hp occurs at a speed of 36-53 km/h and the amount of peak torque released by the motor occurs at a speed of 13 km/h at 228 Nm.

Optimizing Regenerative Braking: A Variational Calculus Approach

We begin by analyzing, using basic physics considerations, under what conditions it becomes energetically favorable to use aggressive regenerative braking to reach a lower speed over “coasting” where one relies solely on air drag to slow down. We then proceed to reformulate the question as an optimization problem to find the velocity profile that maximizes battery charge. Making a simplifying assumption on battery-charging efficiency, we express the recovered energy as an integral quantity, and we solve the associated Euler–Lagrange equation to find the optimal braking curves that maximize this quantity in the framework of variational calculus. Using Lagrange multipliers, we also explore the effect of adding a fixed-displacement constraint.

Determining the Relationship Between the Velocity and Drag Coefficient of a Model Rocket

There has been a significant uptick in interest among the wider public toward space and its associated technologies. Despite this, there is still a significant lack of public resources discussing the more nuanced areas of rocketry. One such area is the behavior of air around a rocket as its speed increases. The changing speed causes the air around the rocket to flow differently, resulting in different drag characteristics. This paper studies this relationship. In keeping with the focus on accessibility, this paper will use a model rocket instead of the full-size version. This paper finds that there is a negative correlation between speed and air drag on a rocket.

Energy Analysis of Highway Electric HDV Platooning Considering Adaptive Downhill Coasting Speed

Increase of non-renewable energy consumption and CO2 emissions has brought heavy burdens to our planet. Heavy-duty vehicles as a large energy consumer benefit a lot from platooning due to reduced air drag. Comparing to ICE trucks, electric trucks can gain more energy savings from platooning while also reducing CO2 emissions. This paper explores the energy consumption of electric HDV platooning under highway situations and proposes an adaptive downhill coasting speed method with regenerative braking. Simulations show that electric HDV platooning can reach at most 33.4% energy savings with our proposed adaptive coasting speed profile. With a sacrifice of 22.2% travel time, the energy savings can be further increased to 49.3%.

Do It Yourself: Air Drag Force Experiment Using Paper and Scraper Sheet

Free fall motion in air medium is only influenced by gravitation acceleration. However, there are several variables that caused the observations to be different with the concept. Variables, such as air drag and terminal velocity, are often teachers not presented in detail, causing misconceptions. This study aims to develop a simple experiment on free fall motion by identifying air drag and terminal velocity. The data in this study is the video of free fall motion of paper and scraper analyzed using Tracker video analyze. From the video analyzed, information is obtained in the form of time (t), track (l, θ), and velocity (v) of the object. This study shows that the air drag force increase unto the terminal velocity. The calculation of the drag coefficient giving the number of the paper 2,16 and the scraper 2,10. According to data analyzed, the air drag force is affected by the mass (m), area (A), and the air drag force (F_D) with the linear correlation until it reaches the terminal velocity. The result of this study may use as references of free fall motion experiment with other objects and analyze.

Pendulum Motion Damped by Speed-Independent Friction

A pendulum without a supporting string or rod is obtained if a small block or marble is released at the rim of a spherical bowl or cylindrical half-pipe. This setup also applies to the familiar loop-the-loop demonstration. However, the bob will then experience sliding or rolling friction, which is speed independent in contrast to the linear or quadratic air drag which is more commonly used to model damping of oscillators. An analytic solution can be found for the speed of the bob as a function of its angular position around the vertical circular trajectory. A numerical solution for the time that the object takes to move from one turning point to the next shows that it is smaller than it would be in the absence of friction.

Distributed Nonlinear Model Predictive Control for Connected Autonomous Electric Vehicles Platoon with Distance-Dependent Air Drag Formulation

This paper addresses the leader tracking problem for a platoon of heterogeneous autonomous connected fully electric vehicles where the selection of the inter-vehicle distance between adjacent vehicles plays a crucial role in energy consumption reduction. In this framework, we focused on the design of a cooperative driving control strategy able to let electric vehicles move as a convoy while keeping a variable energy-oriented inter-vehicle distance between adjacent vehicles which, depending on the driving situation, was reduced as much as possible to guarantee air-drag reduction, energy saving and collision avoidance. To this aim, by exploiting a distance-dependent air drag coefficient formulation, we propose a novel distributed nonlinear model predictive control (DNMPC) where the cost function was designed to ensure leader tracking performances, as well as to optimise the inter-vehicle distance with the aim of reducing energy consumption. Extensive simulation analyses, involving a comparative analysis with respect to the classical constant time headway (CTH) spacing policy, were performed to confirm the capability of the DNMPC in guaranteeing energy saving.