Model Tests on Current Forces on a Large Bridge Pier Near an Existing Pier

2005 ◽  
Vol 127 (3) ◽  
pp. 212-219 ◽  
Author(s):  
Subrata K. Chakrabarti ◽  
Mark McBride
Keyword(s):  
Fluid Velocity ◽  
Three Dimensional ◽  
Suspension Bridge ◽  
Model Tests ◽  
Bridge Pier ◽  
Mooring Line ◽  
Flow Vorticity ◽  
Physical Model Tests ◽  
High Reynolds ◽  
Consistency Of The Test

A suspension bridge is being built over the Tacoma Narrows, Washington. The bridge will be placed on a structure mounted on two large concrete caissons, which will be exposed to strong currents. The piers are of rectangular section with chamfered edges in the upper portion. The caissons are being built at site while floating and moored in high currents. There are no known analytical methods or experimental data available on such structures at high Reynolds number. In order to determine the forces on the caisson due to current, a series of scaled physical model tests of one of the caissons was carried out. The forces on the caisson were measured in the presence of the existing bridge pier and the bottom contours of the Narrows were accurately modeled. The model scale was chosen as 1:100 and the tests were performed for the caisson at different drafts. This paper describes the test setup, and measurement system for a series of fixed caisson tests and demonstrates the consistency of the test data. The measured inline drag and transverse lift forces on the fixed caisson at different drafts are presented and the effect of the fluid velocity and flow vorticity on the frequency contents in the forces is discussed. The interaction effect of the neighboring existing pier on the current forces on the caisson is investigated. Since the measured forces were applied in the design analysis of the caissons, the scaling effect of the model test is also discussed. This paper is accompanied by two other papers, which form a group of three papers related to the project describing the current excitation on the caisson and the associated caisson responses. The other two papers in succession are by Chakrabarti et al. (J. Offshore Mech. Arct. Eng., to be published) and Chakrabarti and McBride (J. Offshore Mech. Arct. Eng., to be published). The paper by Chakrabarti et al. describes the numerical computation of the current forces on the caisson by a three-dimensional analysis, while the paper by Chakrabarti and McBride uses the information from these two papers to determine the motion response of the caissons and the mooring line tensions.

Current Forces on a Large Pier Near an Existing Pier

2004 ◽  
Author(s):  
Subrata K. Chakrabarti ◽  
Mark McBride
Keyword(s):  
High Reynolds Number ◽  
Fluid Velocity ◽  
Suspension Bridge ◽  
Mooring Line ◽  
Cfd Analysis ◽  
Rectangular Section ◽  
Flow Vorticity ◽  
Physical Model Tests ◽  
High Reynolds ◽  
Consistency Of The Test

A new suspension bridge is being built over the Tacoma Narrows, Washington. The bridge will be placed on a structure mounted on 2 large concrete caissons, which will be exposed to strong currents. The piers are of rectangular section with chamfered edges in the upper portion. The caissons are being built at site while floating and moored in high currents. There are no known analytical methods or experimental data available on such structures at high Reynolds number. In order to determine the forces on the caisson due to current, a series of scaled physical model tests of one of the caissons was carried out. The forces on the new caisson were measured in the presence of the existing bridge pier and the bottom contours of the Narrows were accurately modeled. The model scale was chosen as 1:100 and the tests were performed for the caisson at different drafts. This paper describes the test setup, and measurement system for a series of fixed caisson tests and demonstrates the consistency of the test data. The measured inline drag and transverse lift forces on the fixed caisson at different drafts are presented and the effect of the fluid velocity and flow vorticity on the frequency contents in the forces is discussed. The interaction effect of the neighboring existing pier on the current forces of the new caisson is investigated. Since the measured forces were applied in the design analysis of the caissons, the scaling effect of the model test is also discussed. This paper is accompanied by two other papers, which form a group of three papers related to the project describing the current excitation on the caisson and the associated caisson responses. The other two papers in succession are ref. [1] and ref. [2]. The paper in ref. [1] describes the numerical computation of the current forces on the caisson by a 3-D CFD analysis, while the ref. [2] uses the information from these two papers to determine the motion response of the caissons and the mooring line tensions.

Station-Keeping Tests of Moored Caisson in Strong Current

2005 ◽  
Vol 127 (4) ◽  
pp. 315-321 ◽  
Author(s):  
Subrata K. Chakrabarti ◽  
Mark McBride
Keyword(s):  
Suspension Bridge ◽  
Mooring Line ◽  
Mooring Lines ◽  
Construction Period ◽  
Physical Model Tests ◽  
Strong Current ◽  
Highly Nonlinear ◽  
Flow Directions ◽  
Flow Interference ◽  
Line Loads

A new suspension bridge is being built over the Tacoma Narrows, Washington. The bridge will be placed on a structure mounted on two large concrete caissons. The caissons are being constructed in a floating position by pouring concrete at site. During this construction period, the floating caissons are moored in place and will be subject to high currents in the Narrows at a range of drafts. In order to investigate the motions of the caisson and the mooring line loads, physical model tests were performed at a scale of 1:100 at HR Wallingford (HRW). The actual bottom contours of the Narrows near the construction site were duplicated in the model. The catenary mooring lines were highly nonlinear. The current forces and moments on the floating caisson included steady and oscillating components due to flow separation and vortex shedding. There is an existing bridge mounted on two piers in the vicinity of the new caissons, which introduced an appreciable flow interference effect. The tests were conducted in both the ebb and flood flow directions so that the effect of the shadowing of the caisson-pier pair could be studied in the tests. The recorded results of the elastic mooring tests were compared in terms of the maximum measured tensions with a time-domain dynamic motion simulation program, MOTSIM. The results of this comparison are presented in this paper.

Numerical Modelling of Wave Run-Up on a Wind Turbine Foundation

2008 ◽  
Author(s):  
Anders Wedel Nielsen ◽  
Simon Brandi Mortensen ◽  
Vagner Jacobsen ◽  
Erik Damgaard Christensen
Keyword(s):  
Physical Model ◽  
Three Dimensional ◽  
Model Tests ◽  
Offshore Wind ◽  
Offshore Wind Turbines ◽  
Physical Model Tests ◽  
Run Up ◽  
3D Effect ◽  
3D Waves ◽  
Horizontal Bottom

This paper presents the results of a CFD model of the wave run-up on a monopile. The monopile is widely used as the foundation unit for offshore wind turbines. The aim for the calculations is to make a detailed investigation of the effect of three-dimensional (3D) waves on the run-up and to determine the maximum wave run-up. The CFD results are compared with the results of physical model tests conducted under the same conditions. The model tests were conducted under idealized conditions: The tests were carried out on a horizontal bottom using phase and directional focused waves to obtain a 3D effect and at the same time being able to control the breaking. The key objective of this part of the numerical analysis is to develop a model capable of reproducing the results of the physical model tests.

Station-Keeping Tests of Moored Caisson in Strong Current

2004 ◽  
Author(s):  
Subrata K. Chakrabarti ◽  
Mark McBride
Keyword(s):  
Suspension Bridge ◽  
Mooring Line ◽  
Mooring Lines ◽  
Construction Period ◽  
Physical Model Tests ◽  
Strong Current ◽  
Highly Nonlinear ◽  
Flow Directions ◽  
Flow Interference ◽  
Line Loads

A new suspension bridge is being built over the Tacoma Narrows, Washington. The bridge will be placed on a structure mounted on two large concrete caissons. The caissons are being constructed in a floating position by pouring concrete at site. During this construction period, the floating caissons are moored in place and will be subject to high currents in the Narrows at a range of drafts. In order to investigate the motions of the caisson and the mooring line loads, physical model tests were performed at a scale of 1:100 at HR Wallingford (HRW). The actual bottom contours of the Narrows near the construction site was duplicated in the model. The catenary mooring lines were highly nonlinear. The current forces and moments on the floating caisson included steady and oscillating components due to flow separation and vortex shedding. There is an existing bridge mounted on two piers in the vicinity of the new caissons, which introduced an appreciable flow interference effect. The tests were conducted in both the ebb and flood flow directions so that the effect of the shadowing of the caisson-pier pair could be studied in the tests. The recorded results of the elastic mooring tests were compared in terms of the maximum measured tensions with a time-domain dynamic motion simulation program, MOTSIM. The results of this comparison are presented in this paper.

scholarly journals Modeling of three-dimensional exciplex pumped fluid Cs vapor laser with transverse and longitudinal gas flow

2021 ◽  
Vol 9 ◽  
Author(s):  
Chenyi Su ◽  
Xingqi Xu ◽  
Jinghua Huang ◽  
Bailiang Pan
Keyword(s):  
Wall Temperature ◽  
Laser Power ◽  
Gas Flow ◽  
Particle Density ◽  
Fluid Velocity ◽  
Three Dimensional ◽  
Heat Accumulation ◽  
Vapor Laser ◽  
Output Laser Power ◽  
Output Laser

Abstract Considering the thermodynamical fluid mechanics in the gain medium and laser kinetic processes, a three-dimensional theoretical model of an exciplex-pumped Cs vapor laser with longitudinal and transverse gas flow is established. The slope efficiency of laser calculated by the model shows good agreement with the experimental data. The comprehensive three-dimensional distribution of temperature and particle density of Cs is depicted. The influence of pump intensity, wall temperature, and fluid velocity on the laser output performance is also simulated and analyzed in detail, suggesting that a higher wall temperature can guarantee a higher output laser power while causing a more significant heat accumulation in the cell. Compared with longitudinal gas flow, the transverse flow can improve the output laser power by effectively removing the generated heat accumulation and alleviating the temperature gradient in the cell.

scholarly journals Effect of buried depth on thermal performance of a vertical U-tube underground heat exchanger

Open Physics ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 327-330
Author(s):  
Li Yang ◽  
Bo Zhang ◽  
Jiří Jaromír Klemeš ◽  
Jie Liu ◽  
Meiyu Song ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Fluid Velocity ◽  
Three Dimensional ◽  
Simplified Model ◽  
Two Dimensional ◽  
Construction Sites ◽  
Full Size ◽  
Unit Depth ◽  
Research Show

Abstract Many researchers numerically investigated U-tube underground heat exchanger using a two-dimensional simplified pipe. However, a simplified model results in large errors compared to the data from construction sites. This research is carried out using a three-dimensional full-size model. A model validation is conducted by comparing with experimental data in summer. This article investigates the effects of fluid velocity and buried depth on the heat exchange rate in a vertical U-tube underground heat exchanger based on fluid–structure coupled simulations. Compared with the results at a flow rate of 0.4 m/s, the results of this research show that the heat transfer per buried depth at 1.0 m/s increases by 123.34%. With the increase of the buried depth from 80 to 140 m, the heat transfer per unit depth decreases by 9.72%.

scholarly journals Modelling of Applied Magnetic Field and Thermal Radiations Due to the Stretching of Cylinder

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1077
Author(s):  
Muhammad Tamoor ◽  
Muhammad Kamran ◽  
Sadique Rehman ◽  
Aamir Farooq ◽  
Rewayat Khan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Fluid Velocity ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Skin Friction Coefficient ◽  
Physical Parameters ◽  
Boundary Layer Equations ◽  
Convective Parameter ◽  
Momentum And Heat Transfer ◽  
Dimensional Boundary

In this study, a numerical approach was adopted in order to explore the analysis of magneto fluid in the presence of thermal radiation combined with mixed convective and slip conditions. Using the similarity transformation, the axisymmetric three-dimensional boundary layer equations were reduced to a self-similar form. The shooting technique, combined with the Range–Kutta–Fehlberg method, was used to solve the resulting coupled nonlinear momentum and heat transfer equations numerically. When physically interpreting the data, some important observations were made. The novelty of the present study lies in finding help to control the rate of heat transfer and fluid velocity in any industrial manufacturing processes (such as the cooling of metallic plates). The numerical results revealed that the Nusselt number decrease for larger Prandtl number, curvature, and convective parameters. At the same time, the skin friction coefficient was enhanced with an increase in both slip velocity and convective parameter. The effect of emerging physical parameters on velocity and temperature profiles for a nonlinear stretching cylinder has been thoroughly studied and analyzed using plotted graphs and tables.

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