A Numerical Study on the Launching Angle for the Maximum Range of a Projectile with a Linear Drag Force

2012 ◽  
Vol 62 (8) ◽  
pp. 870-875
Author(s):  
Chang-Young LEE*
Keyword(s):  
Drag Force ◽  
Numerical Study ◽  
Maximum Range ◽  
Linear Drag

scholarly journals Electrodynamics of a magnet moving through a conducting pipe

2006 ◽  
Vol 84 (4) ◽  
pp. 253-271 ◽  
Author(s):  
M Hossein Partovi ◽  
Eliza J Morris
Keyword(s):  
Drag Force ◽  
Eddy Currents ◽  
Numerical Study ◽  
Full Range ◽  
Magnetic Behavior ◽  
Integral Form ◽  
Asymptotic Formulas ◽  
Pipe Material ◽  
Point Dipole ◽  
Axially Symmetric

The popular demonstration involving a permanent magnet falling through a conducting pipe is treated as an axially symmetric boundary-value problem. Specifically, Maxwell's equations are solved for an axially symmetric magnet moving coaxially inside an infinitely long, conducting cylindrical shell of arbitrary thickness at nonrelativistic speeds. Analytic solutions for the fields are developed and used to derive the resulting drag force acting on the magnet in integral form. This treatment represents a significant improvement over existing models, which idealize the problem as a point dipole moving slowly inside a pipe of negligible thickness. It also provides a rigorous study of eddy currents under a broad range of conditions, and can be used for magnetic braking applications. The case of a uniformly magnetized cylindrical magnet is considered in detail, and a comprehensive analytical and numerical study of the properties of the drag force is presented for this geometry. Various limiting cases of interest involving the shape and speed of the magnet and the full range of conductivity and magnetic behavior of the pipe material are investigated and corresponding asymptotic formulas are developed.PACS Nos.: 81.70.Ex, 41.20.–q, 41.20.Gz

The numerical study of viscous drag force influence on low-frequency surge motion of a semi-submersible in storm sea states

2020 ◽  
Vol 213 ◽  
pp. 107511 ◽  
Author(s):  
Shan Ma ◽  
De-kang Xu ◽  
Wen-yang Duan ◽  
Ji-kang Chen ◽  
Kang-ping Liao ◽  
...  
Keyword(s):  
Drag Force ◽  
Numerical Study ◽  
Low Frequency ◽  
Viscous Drag ◽  
Viscous Drag Force

scholarly journals A rigorous mathematical treatment of the shape of a dissipative rope fountain

2019 ◽  
Vol 475 (2231) ◽  
pp. 20190612
Author(s):  
Jonathan J. Bevan ◽  
Jonathan H. B. Deane
Keyword(s):  
Energy Conservation ◽  
Drag Force ◽  
Numerical Study ◽  
Analytical Description ◽  
Mathematical Treatment ◽  
Numerical Treatment ◽  
Constant Tension ◽  
Free Case ◽  
Parameter Values

This is a theoretical and numerical study of a model of a rope fountain subject to a drag force that depends linearly on the rope velocity. A precise, analytical description of the long-term shape adopted by the rope is given, and various consequences are derived from it. Using parameters that naturally appear in the model, we distinguish between cases wherein energy is conserved by means of a constant tension far from the rope source (the ‘free’ case) and where energy conservation is a consequence of a non-constant tension (the ‘braked’ case). The model is used, among other things, to generate rope fountain shapes based on approximate experimental estimates of the parameter values and a careful numerical treatment.

Numerical Study on Film Foam Flow Characteristics in a Straight Duct

2013 ◽  
Vol 561 ◽  
pp. 472-477 ◽  
Author(s):  
Dong Xing Du ◽  
Fa Hu Zhang ◽  
Dian Cai Geng ◽  
Ying Ge Li
Keyword(s):  
Drag Force ◽  
Pressure Difference ◽  
Numerical Study ◽  
Flow Behavior ◽  
Petroleum Industry ◽  
Flow Characteristics ◽  
Viscous Force ◽  
Ideal Condition ◽  
Surface Evolver ◽  
The Mathematical Model

Straight ducts capture some essential features of the motion of foam in porous media in petroleum industry. In this paper, Surface Evolver was employed to build the mathematical model to study the flow behavior of lamellas in the duct with different models. Numerical results show good agreement with experiments and some important features of lamella flow behavior in straight ducts are obtained. It is concluded that, the physical model with viscous force can adequately describe the flow characteristics of reality foam in the experiment. The actual pressure difference consists of the pressure difference caused by the curvature of the lamellas and the drag force on the boundary wall. Under the ideal condition of without drag force along the wall, the pressure drop for lamella flow in the duct is zero, and the shape and the velocity of the lamellas will maintain constant.

scholarly journals Numerical Study of Hydrodynamic Forces for AFM Operations in Liquid

Scanning ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Tobias Berthold ◽  
Guenther Benstetter ◽  
Werner Frammelsberger ◽  
Rosana Rodríguez ◽  
Montserrat Nafría
Keyword(s):  
Drag Force ◽  
Numerical Study ◽  
Viscous Friction ◽  
Hydrodynamic Drag ◽  
Water Mixture ◽  
Ultrapure Water ◽  
Liquid Environment ◽  
Drag Forces ◽  
Organic Sample ◽  
Repulsive Forces

For advanced atomic force microscopy (AFM) investigation of chemical surface modifications or very soft organic sample surfaces, the AFM probe tip needs to be operated in a liquid environment because any attractive or repulsive forces influenced by the measurement environment could obscure molecular forces. Due to fluid properties, the mechanical behavior of the AFM cantilever is influenced by the hydrodynamic drag force due to viscous friction with the liquid. This study provides a numerical model based on computational fluid dynamics (CFD) and investigates the hydrodynamic drag forces for different cantilever geometries and varying fluid conditions for Peakforce Tapping (PFT) in liquids. The developed model was verified by comparing the predicted values with published results of other researchers and the findings confirmed that drag force dependence on tip speed is essentially linear in nature. We observed that triangular cantilever geometry provides significant lower drag forces than rectangular geometry and that short cantilever offers reduced flow resistance. The influence of different liquids such as ultrapure water or an ethanol-water mixture as well as a temperature induced variation of the drag force could be demonstrated. The acting forces are lowest in ultrapure water, whereas with increasing ethanol concentrations the drag forces increase.

Full-Scale Simulation-Based Hull Form Design for Large Medium-Speed Catamarans with High Fuel Efficiency

2015 ◽  
Author(s):  
Max Haase ◽  
Gary Davidson ◽  
Stuart Friezer ◽  
Jonathan Binns ◽  
Giles Thomas ◽  
...  
Keyword(s):  
Drag Force ◽  
Numerical Study ◽  
Fuel Efficiency ◽  
Full Scale ◽  
Hull Form ◽  
High Fuel Efficiency ◽  
Medium Speed ◽  
Simulation Based ◽  
Form Design ◽  
Hull Form Design

This paper reports on a numerical study to obtain the full-scale drag force for large catamarans of 110 m to 190 m in length at medium speeds of Froude numbers between 0.25 and 0.49, which comprises vessel speeds from 16 to 41 knots. The paper concludes with appropriate values of slenderness ratios and transom immersion for the lowest total resistance at different Froude numbers, and appropriate hull lengths to achieve highest possible fuel efficiency for different drafts at speeds between 24 and 33 knots. These slenderness ratios, for lowest drag force, were determined at different Froude numbers of 0.25, 0.37 and 0.45.

scholarly journals Numerical study of the hydrodynamic drag force in atomic force microscopy measurements undertaken in fluids

Micron ◽  
2014 ◽  
Vol 66 ◽  
pp. 37-46 ◽  
Author(s):  
J.V. Méndez-Méndez ◽  
M.T. Alonso-Rasgado ◽  
E. Correia Faria ◽  
E.A. Flores-Johnson ◽  
R.D. Snook
Keyword(s):  
Atomic Force Microscopy ◽  
Drag Force ◽  
Numerical Study ◽  
Hydrodynamic Drag ◽  
Force Microscopy ◽  
Atomic Force

Numerical Study of Improving Aerodynamic Performance of the Cylinder Airfoil of Magnus Wind Turbine

2013 ◽  
Vol 650 ◽  
pp. 414-419
Author(s):  
Qi Yao ◽  
Ying Xue Yao ◽  
Liang Zhou ◽  
Jin Ming Wu ◽  
Jian Guang Li
Keyword(s):  
Fluid Dynamics ◽  
Drag Force ◽  
Numerical Study ◽  
Rotating Cylinder ◽  
Aerodynamic Performance ◽  
Orthogonal Test ◽  
Performance Change ◽  
Result Show ◽  
Drag Ratio ◽  
Lift To Drag Ratio

To solve the problem of low lift to drag ratio of Magnus cylinder airfoil, the Computational Fluid Dynamics software Fluent was used to study the principle of a drop of the drag force of cylinder when rotating. And the principle was used to further reduce the drag of rotating cylinder. A traditional airfoil head and a triangle tail was used to study the effect of the aerodynamic performance change of the combined airfoil. A conclusion was made that with a suitable profile of the tail would reduce the drag force of the combined airfoil thus increase the lift to drag ratio of the airfoil. At last an orthogonal test was made to determine the size of the tail airfoil. The result show that the optimized airfoil reduce the drag force to 50% of the original cylinder and improve the lift to drag ratio to 50%.

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