A stable algorithm for bed friction in three-dimensional shallow sea modal models

1992 ◽  
Vol 14 (4) ◽  
pp. 477-493 ◽  
Author(s):  
A. M. Davies ◽  
J. N. Aldridge
Keyword(s):  
Three Dimensional ◽  
Shallow Sea ◽  
Stable Algorithm ◽  
Bed Friction

A Three-Dimensional Model of Shallow-Sea Fronts

1983 ◽  
pp. 173-184 ◽  
Author(s):  
I. D. James
Keyword(s):  
Three Dimensional ◽  
Dimensional Model ◽  
Shallow Sea ◽  
Three Dimensional Model

Three-dimensional Acoustic Effect by Seamounts in Shallow Sea

2021 ◽  
Author(s):  
Qile Wang ◽  
Wei Zhang ◽  
Hanhao Zhu ◽  
Zhiqiang Cui ◽  
Yangyang Xue
Keyword(s):  
Three Dimensional ◽  
Shallow Sea ◽  
Acoustic Effect

Experimental investigation and modeling study of the fiber orientation behavior

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Maoyuan Li ◽  
Yun Zhang ◽  
Shi Zhang ◽  
Binkui Hou ◽  
Huamin Zhou
Keyword(s):  
Fiber Orientation ◽  
Integral Transformation ◽  
Three Dimensional ◽  
Numerical Algorithms ◽  
Tensile Specimen ◽  
Transformation Method ◽  
Orientation Behavior ◽  
Stable Algorithm ◽  
Content Type ◽  
The Stability

Purpose The orientation behavior of fiber is of great significance in improving the performance of fiber-reinforced polymer products. Generally, the Folgar–Tucker equation can accurately describe the variation of orientation vector of fiber, whereas the stability of numerical algorithms was the major challenge. This paper aims to propose an accurate, stable algorithm to solve the Folgar–Tucker equation for the fiber orientation behavior. Design/methodology/approach First, the mismatch problem between the strain rate and the pressure field was solved by using the integral transformation method. Then, an accurate, stable algorithm to solve the Folgar–Tucker equation based on the invariant-based optimal fitting method was proposed. The equation was discretized by finite element/finite difference method, and the Lagrange multiplier method was applied to ensure stability. Findings The proposed algorithm is proven to accurately and steadily coincide with the experimental results for different cases, including the fiber orientation behaviors under combined flow field, rectangular sheet, three-dimensional computed tomography imaging of tensile specimen and box cases. Originality/value The fiber orientation behavior during the injection molding can be accurately predicted, which plays a significant role in determining the mechanical properties of products.

Application of the three-dimensional shallow sea and continental shelf mode for inversion of undercurrent

2006 ◽  
Vol 11 (2) ◽  
pp. 377-380
Author(s):  
Wen Biyang ◽  
Hong Chun ◽  
Wu Rui
Keyword(s):  
Continental Shelf ◽  
Three Dimensional ◽  
Shallow Sea

scholarly journals Three-Dimensional Unified Motion Control of a Robotic Standing Wheelchair for Rehabilitation Purposes

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 3057
Author(s):  
Jessica S. Ortiz ◽  
Guillermo Palacios-Navarro ◽  
Víctor H. Andaluz ◽  
Luis F. Recalde
Keyword(s):  
Computational Cost ◽  
Three Dimensional ◽  
Robustness Analysis ◽  
Sampling Period ◽  
Secondary Tasks ◽  
Stable Algorithm ◽  
Technological Advances ◽  
Control Scheme ◽  
Motion Problem ◽  
The Stability

Technological advances in recent years have shown interest in the development of robots in the medical field. The integration of robotic systems in areas of assistance and rehabilitation improves the user’s quality of life. In this context, this article presents a proposal for the unified control of a robotic standing wheelchair. Considering primary and secondary tasks as control objectives, the system performs tasks autonomously and the change of position and orientation can be performed at any time. The development of the control scheme was divided in two parts: (i) kinematic controller to solve the desired motion problem; and (ii) dynamic compensation of the standing wheelchair–human system. The design of the two controllers considers the theory of linear algebra, proposing a low computational cost and an asymptotically stable algorithm, without disturbances. The stability and robustness analysis of the system is performed by analyzing the evolution of the control errors in each sampling period. Finally, real experiments of the performance of the developed controller are performed using a built and instrumented standing wheelchair.

Unconditionally Stable Algorithm for Solving the Three-Dimensional Nonstationary Navier–Stokes Equations

2018 ◽  
Vol 54 (7) ◽  
pp. 979-992
Author(s):  
O. A. Shatrov ◽  
O. V. Shcheritsa ◽  
O. S. Mazhorova
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Unconditionally Stable ◽  
Navier Stokes Equations ◽  
Stable Algorithm

Three-dimensional surges and recoveries in a numerical glacier model

1969 ◽  
Vol 6 (4) ◽  
pp. 979-986 ◽  
Author(s):  
William J. Campbell ◽  
Lowell A. Rasmussen
Keyword(s):  
Steady State ◽  
High Speed ◽  
Three Dimensional ◽  
Volume Transport ◽  
Navier Stokes ◽  
Physical Parameters ◽  
Navier Stokes Equation ◽  
Total Recovery ◽  
Flow Equations ◽  
Bed Friction

The Navier–Stokes equation, integrated vertically to yield a two-dimensional transport equation, is combined with the three-dimensional continuity equation. By assuming a linear relation between volume transport and bottom shear stress, a system of numerically tractable differential equations is developed that contains a nonlinear surface slope term and a term in which horizontal frictional forces are stated explicitly. These equations, which are not based on perturbation analysis, are integrated directly on a high speed digital computer. The coefficient of each term in the flow equations is composed of physical parameters (gravity, density, viscosity); therefore, since no quantities such as ice velocities enter the equations, it is only necessary to specify an arbitrary bed configuration and a net-balance versus altitude curve to obtain a glacier solution.For two beds, valley and cirque, steady-state glacier solutions are found for a variety of bed and lateral frictional values. By reducing the bed friction coefficient for one year over the entire bed of the glacier, surges are induced in each of these cases. A reduction in bed friction to 5% of its original value yields a surge resembling typical observed surges. Interesting wave forms occur during the recovery. During the initial recovery, after the bed friction has been restored to its original value, height falls continue to occur even in the lower accumulation zone. The original steady-state shape is approached asymptotically, with total recovery taking hundreds of years.

Sign in / Sign up

Export Citation Format

Share Document