A three-dimensional model for analyzing the effects of salmon redds on hyporheic exchange and egg pocket habitat

2009 ◽  
Vol 66 (12) ◽  
pp. 2157-2173 ◽  
Author(s):  
Daniele Tonina ◽  
John M. Buffington
Keyword(s):  
Fluid Dynamics ◽  
Hydraulic Conductivity ◽  
Dissolved Oxygen ◽  
Oxygen Content ◽  
Three Dimensional ◽  
Hyporheic Exchange ◽  
Dimensional Model ◽  
Dynamics Model ◽  
Three Dimensional Model ◽  
Channel Hydraulics

A three-dimensional fluid dynamics model is developed to capture the spatial complexity of the effects of salmon redds on channel hydraulics, hyporheic exchange, and egg pocket habitat. We use the model to partition the relative influences of redd topography versus altered hydraulic conductivity (winnowing of fines during spawning) on egg pocket conditions for a simulated pool–riffle channel with a redd placed at the pool tail. Predictions show that altered hydraulic conductivity is the primary factor for enhancing hyporheic velocities and dissolved oxygen content within the egg pocket. Furthermore, the simulations indicate that redds induce hyporheic circulation that is nested within that caused by pool–riffle topography and that spawning-related changes in hyporheic velocities and dissolved oxygen content could create conditions suitable for incubation in locations that otherwise would be unfavorable (reinforcing the notion that salmonids actively modify their environment in ways that may be beneficial to their progeny).

scholarly journals Numerical Simulation of a Propeller-Type Turbine for In-Pipe Installation

2021 ◽  
Vol 83 (1) ◽  
pp. 1-16
Author(s):  
Oscar Darío Monsalve Cifuentes ◽  
Jonathan Graciano Uribe ◽  
Diego Andrés Hincapié Zuluaga
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Pipe Wall ◽  
Three Dimensional ◽  
Hydraulic Efficiency ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Mesh Independence ◽  
Using Data

In this work, a 76 mm diameter propeller-type turbine is numerically investigated using a parametric study and computational fluid dynamics. The three-dimensional model of the turbine is modeled using data available in the bibliography. A mesh independence study is carried out utilizing a tetrahedron-based mesh with inflation layers around the turbine blade and the pipe wall. The best efficiency point is determined by the maximum hydraulic efficiency of 64.46 %, at a flow rate of 9.72x10-3 m3/s , a head drop of 1.76 m, and a mechanical power of 107.83 W. Additionally, the dimensionless distance y+, pressure, and velocity contours are shown.

Dynamics of moving-object grasped by a hybrid hand

2021 ◽  
pp. 146441932110511
Author(s):  
Yi Lu ◽  
Zefeng Chang ◽  
Nijia Ye
Keyword(s):  
Parallel Manipulator ◽  
Jacobian Matrix ◽  
Hessian Matrix ◽  
Three Dimensional ◽  
Moving Object ◽  
Dimensional Model ◽  
Dynamics Model ◽  
Three Dimensional Model ◽  
Precision Grasping ◽  
General Velocity

When a heavy object is cooperatively grasped to move by several fingers of the robot hybrid hand, the inertial properties and the mass distribution of the object must influence largely on the operation precision, grasping stability, and the safety of both the hybrid hand and the object. Hence, it is an important and significant issue to establish and analyze the dynamics model of the moving-object cooperatively grasped by the hybrid hand in order to ensure the safety and grasping stability of the hybrid hand and the object. However, this research has not been conducted. In this paper, a dynamics model of the moving-object grasped by the hybrid hand is established, and its dynamics is studied and analyzed. First, a three-dimensional model of a hybrid hand formed by a novel parallel manipulator and three fingers is designed for cooperatively grasping object. Second, the kinematic formulas for solving the Jacobian matrices, the Hessian matrices, the general velocity/acceleration of the moving platform, and four active limbs of the parallel manipulator are derived. Third, the composite Jacobian matrix and the composite Hessian matrix of the hybrid hand are derived, and the general velocity/acceleration of the moving-object grasped by the hybrid hand is derived. Fourth, dynamics model of the hybrid hand is established, the formulas for solving the dynamic actuation forces of the three fingers and the dynamic actuation forces/torque and constrained forces of the parallel manipulator are derived. Finally, the theoretical solutions of the dynamics model of the moving-object grasped by the hybrid hand are verified by its simulation mechanism.

scholarly journals Design of a three-dimensional hand/forearm model to apply computational fluid dynamics

2010 ◽  
Vol 53 (2) ◽  
pp. 436-442 ◽  
Author(s):  
Daniel Almeida Marinho ◽  
Victor Machado Reis ◽  
João Paulo Vilas-Boas ◽  
Francisco Bessone Alves ◽  
Leandro Machado ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Three Dimensional ◽  
Digital Model ◽  
Human Hand ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Perfect Agreement ◽  
Computational Data ◽  
Processing Techniques

The purpose of this study was to develop a three-dimensional digital model of a human hand and forearm to apply Computational Fluid Dynamics to propulsion analysis in swimming. Computer tomography scans of the hand and forearm of an Olympic swimmer were applied. The data were converted, using image processing techniques, into relevant coordinate input, which could be used in Computational Fluid Dynamics software. From that analysis, it was possible to verify an almost perfect agreement between the true human segment and the digital model. This technique could be used as a means to overcome the difficulties in developing a true three-dimensional model of a specific segment of the human body. Additionally, it could be used to improve the use of Computational Fluid Dynamics generally in sports and specifically in swimming studies, decreasing the gap between the experimental and the computational data.

scholarly journals Groundwater Simulation and Wells Distribution at Qazaniyah City in Diyala Governorate

2020 ◽  
Vol 26 (9) ◽  
pp. 95-113
Author(s):  
Majed Rodhan Huseen ◽  
Basim Sh. Abed
Keyword(s):  
Hydraulic Conductivity ◽  
Groundwater Modeling ◽  
Three Dimensional ◽  
Alluvial Fan ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Main Layer ◽  
Operating Rate ◽  
Gis Software ◽  
Observation Wells

In recent years, there is more interest in water sources availability, including groundwater due to an increase in demand for water because of the increasing population in the world, and the water recedes due to climate change also. Therefore, the study of groundwater has required more attention. The aim of the present study is to establish a MODFLOW model in the groundwater modeling system software to simulate the movement of groundwater in the Turssaq alluvial fan which is located in the Qazaniyah city, east of Diyala Governorate. The solid model was used to define the aquifer in the study area. Using the GIS software, mapping and preparing the data needed to create a conceptual model were carried out. The data of the wells were used to create and define the aquifer, then a three-dimensional model was created. Measuring the water table for some wells were simultaneously monitored to determine the hydraulic conductivity values ​​of the aquifer through the (PEST) package provided by the software. The hydraulic conductivity value of the main layer was 18 m/d. Then several readings of observation wells were recorded for the period extended from 1/Nov/2018 to 22/May/2019 for the calibration process in the unsteady situation and to determine the coefficient of storage. The value of the storage coefficient was defined as 0.001. Several scenarios were conducted for the study area to find the best distance between the wells. Three distances were tested, 500, 1000 and 1500 m. The operating periods were 6, 12 and 18 (hours/day). Results obtained from the model show that the best distance between the wells is 1000 meters with a maximum operating rate of 12 hours/day. The maximum discharge with the lowest distance and the lowest drawdown of the groundwater table are considered.

Numerical Simulation on Solidification of Flow inside an Elliptical Pipe

2015 ◽  
Vol 799-800 ◽  
pp. 751-755
Author(s):  
Lan Li ◽  
Huan Ma ◽  
Feng Qi Si ◽  
Kang Ping Zhu
Keyword(s):  
Heat Transfer ◽  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Three Dimensional ◽  
Short Axis ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Axis Direction ◽  
Lower Reynolds Number ◽  
Flow Through

The aim of this investigation is to study the characteristics of solidification of flow through an elliptical pipe and to avoid the solidification and blockage in the pipe. A three-dimensional model has been completed using the commercial fluid dynamics code, Fluent. Analyses under different conditions show that different factors affect the characteristics of solidification and heat transfer in the pipe. The lower Reynolds number is or the higher dimensionless wall temperature turns, the thicker the ice layer becomes, which will increase the risk of blockage. The thickness at the long axis direction will grow with the increase of ellipse aspect ratio while it turns out contrary at short axis direction.

A three-dimensional model of the fluid dynamics of radio-trail sources

Nature ◽  
1984 ◽  
Vol 310 (5972) ◽  
pp. 33-36 ◽  
Author(s):  
A. G. Williams ◽  
S. F. Gull
Keyword(s):  
Fluid Dynamics ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model

The Calculation and Analysis of the Yacht Engine Cooling Water Jacket Based on the CFD Technology

2013 ◽  
Vol 278-280 ◽  
pp. 245-250
Author(s):  
Yu Gang Jin ◽  
Jing Yang ◽  
Ke Li
Keyword(s):  
Fluid Dynamics ◽  
Water Distribution ◽  
Cooling System ◽  
Three Dimensional ◽  
Cooling Water ◽  
Internal Flow ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Water Jacket ◽  
Engine Cooling

The paper takes a yacht engine as the research object. Build a three dimensional model of one yacht engine cooling water jacket through the Pro/E software. Make analysis of internal flow field of cooling water distribution, pressure loss, and so on, with the computational fluid dynamics software—STAR-CCM+. Find problems in the cooling system, and propose improvements for the engine cooling water jacket and evaluate the program and conduct a comparative analysis of the original program.

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