Dynamics of a Pipe Aspirating Fluid Such as Might be Used in Ocean Mining

1985 ◽  
Vol 107 (2) ◽  
pp. 250-255 ◽  
Author(s):  
M. P. Paidoussis ◽  
T. P. Luu
Keyword(s):  
Internal Flow ◽  
Large Mass ◽  
Wave Action ◽  
Mining System ◽  
Fluid Medium ◽  
Small Flow ◽  
Marine Currents ◽  
Cantilevered Pipe ◽  
Ocean Mining ◽  
Passive Stabilization

This paper presents an investigation into the dynamics and stability of a long, vertically disposed, cantilevered pipe, submerged in and aspirating fluid from the free lower end, and conveying it upwards to the supported upper end; the pipe has a large mass attached to its free end. The arrangement represents an idealization of an ocean mining system. This paper reports on the first phase of this work, in which the following simplifications have been made: (i) the pipe is straight at equilibrium; (ii) the effects of marine currents and wave action are not considered. It is shown that under the action of the internal flow, the system is inherently unstable, by flutter, and that it does not lose stability at vanishingly small flow velocities, only because of dissipation, through friction with the external fluid medium. Effective passive stabilization of the system may be achieved through artificial augmentation of this form of dissipation.

Heave Induced Internal Flow Fluctuations in Vertical Transport Systems for Deep Ocean Mining

2014 ◽  
Author(s):  
Stephan D. A. Hannot ◽  
Jort M. van Wijk
Keyword(s):  
Transport System ◽  
Internal Flow ◽  
Deep Ocean ◽  
Vertical Transport ◽  
Transport Systems ◽  
Ship Motions ◽  
Centrifugal Pumps ◽  
Mining System ◽  
Pump System ◽  
Ocean Mining

Deep ocean mining systems will have to operate often in harsh weather conditions with heavy sea states. A typical mining system consists of a Mining Support Vessel (MSV) with a Vertical Transport System (VTS) attached to it. The transport system is a pump pipeline system using centrifugal pumps. The heave motions of the ship are transferred to the pump system due to the riser-ship coupling. Ship motions thus will have a significant influence on the internal flow in the VTS. In this paper, the influence of heave motions on the internal flow in the VTS for a typical mining system for Seafloor Massive Sulfide (SMS) deposits in Papua New Guinea is analyzed. Data on the wave climate in the PNG region is used to compute the ship motions of a coupled MSV-VTS. The ship motions then are translated into forces acting on the internal flow in order to compute fluctuations in the internal flow. In this way, the workability of the mining system with respect to the system’s production can be assessed. Based on a detailed analysis of the internal flow in relation to ship motions, the relevance of a coupled analysis for the design of VTS is made clear. This paper provides a method for performing such analyses.

The Dynamics of a Cantilevered Pipe Aspirating Fluid Studied by Experimental, Numerical and Analytical Methods

2010 ◽  
Author(s):  
Dana Giacobbi ◽  
Stephanie Rinaldi ◽  
Christian Semler ◽  
Michael P. Pai¨doussis
Keyword(s):  
Analytical Model ◽  
Low Flow ◽  
Computational Fluid Dynamics Cfd ◽  
Computational Structural Mechanics ◽  
Cantilevered Pipe ◽  
The Galerkin Method ◽  
Csm Model ◽  
Ocean Mining ◽  
Flow Experiments ◽  
Flow Velocities

This paper investigates the dynamics of a slender, flexible, aspirating cantilevered pipe, ingesting fluid at its free end and conveying it towards its clamped end. The problem is interesting not only from a fundamental perspective, but also because applications exist, notably in ocean mining [1]. First, the need for the present work is demonstrated through a review of previous research into the topic — spanning many years and yielding often contradictory results — most recently concluding that the system loses stability by flutter at relatively low flow velocities [2]. In the current paper, that conclusion is refined and expanded upon by exploring the problem in three ways: experimentally, numerically and analytically. First, air-flow experiments, in which the flow velocity of the fluid was varied and the frequency and amplitude of oscillation of the pipe were measured, were conducted using different elastomer pipes and intake shapes. Second, a fully-coupled Computational Fluid Dynamics (CFD) and Computational Structural Mechanics (CSM) model was developed in ANSYS in order to simulate experiments and corroborate experimental results. Finally, using an analytical approach, the existing linear equation of motion describing the system was significantly improved upon, and then solved via the Galerkin method in order to determine its stability characteristics. Heavily influenced by a CFD analysis, the proposed analytical model is different from previous ones, most notably because of the inclusion of a two-part fluid depressurization at the intake. In general, both the actual and numerical experiments suggest a first-mode loss of stability by flutter at relatively low flow velocities, which agrees with the results from the new analytical model.

Dynamic Model Development and Simulation Analysis of China’s Total Integrated Deep Ocean Mining Pilot System

2010 ◽  
Author(s):  
Yu Dai ◽  
Shaojun Liu ◽  
Li Li ◽  
Yan Li ◽  
Gang Wang ◽  
...  
Keyword(s):  
Dynamic Analysis ◽  
Deep Ocean ◽  
Pipeline System ◽  
Mining System ◽  
Fem Model ◽  
Body Model ◽  
Single Body ◽  
Operation Process ◽  
Ocean Mining ◽  
Dem Model

A typical and may be the most prospective deep ocean mining system is an integration of a mining ship system, a hoist pipeline system and a self-propelled seafloor miner system. According to this representative system configuration, China has designed and developed a deep ocean mining pilot system. In order to evaluate and improve the design of the pilot system, and further to provide technical references for the practical system operation, dynamic simulation models of the subsystems and the total integrated system are developed. For the seafloor miner, a multi-body model with the scale of 1:1 to the actual size of the pilot miner is built, which can be used effectively to perform detailed design, analysis and optimization of the miner system. Meanwhile, to make the integration of the total mining system possible, a simplified 3D single-body model with 6 DOF of the miner is also developed, which is capable of real-time simulation and can be easily integrated with other subsystems. For the pipeline system including the rigid lifting pipe, submerged pump, buffer storage and flexible hose, finite element method (FEM) and discrete element method (DEM) are all proposed and developed. With the FEM model, the towing mining operation process, as well as the launching and retrieval process, can be analyzed. Whereas, the DEM model is preferred to perform the dynamic analysis of the total integrated mining system due to its relative high computation efficiency compared with that of the FEM model. To realize the dynamic analysis of the total integrated mining system with relative high efficiency and accuracy, the single body model of the miner and the DEM model of the pipeline are chosen to be integrated to form the total system and perform dynamic analysis, which in a way can provide specific guidance and suggestions for the practical deep ocean mining system analysis, operation and control. For further researches, more attention will be focused on the analysis of the launching and retrieval operation process of the total mining system, including the water entry of the miner, the launching process of the pipeline system and the final seafloor-touchdown of the miner.

A Coupled Two-Way Fluid-Structure Interaction Analysis for the Dynamics of a Partially Confined Cantilevered Pipe Under Simultaneous Internal and External Axial Flow in Opposite Directions

2021 ◽  
Author(s):  
Farhang Daneshmand ◽  
Tahereh Liaghat ◽  
Michael Paidoussis
Keyword(s):  
Interaction Analysis ◽  
Velocity Ratio ◽  
Fluid Structure Interaction ◽  
Axial Flow ◽  
Internal Flow ◽  
Structural Domain ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Cantilevered Pipe ◽  
Central Pipe

Abstract This paper presents the results of a coupled two-way fluid-structure interaction analysis of a slender flexible vertical cantilevered pipe hanging concentrically within a shorter rigid tube forming an annulus. The pipe is subjected to internal and annular flows simultaneously. This system has applications in brine production and salt-cavern hydrocarbon storage. In the present study, the fluid-structure problem is solved with a finite-volume-based CFD code for the fluid domain coupled to a finite-element-based CSM code for the structural domain. The numerical results obtained for the free-end displacement of the central pipe versus the annular/internal flow velocity ratio U_o/U_i are presented and compared with those obtained from experiment. The capability of the numerical model to predict the onset of the experimentally observed flutter instability in the system is also examined. This provides a better insight into the dynamics of the system.

Diagnosis of the anaerobic reject water effects on WWTP operational characteristics as a precursor of bulking and foaming

2014 ◽  
Vol 71 (4) ◽  
pp. 572-579 ◽  
Author(s):  
Dilek Erdirençelebi ◽  
Murat Küçükhemek
Keyword(s):  
Plug Flow ◽  
Treatment Plant ◽  
Internal Flow ◽  
Volume Index ◽  
Operational Parameters ◽  
Anaerobic Digesters ◽  
Reject Water ◽  
Solids Concentration ◽  
Water Effects ◽  
Small Flow

This study investigates the effects observed on operational parameters in a large and full-scale wastewater treatment plant subjected to anaerobic reject water (ARW) diversion off the main line for a 3-month period and further monitoring for a 2-year period. The plant's secondary unit consists of a two-stage plug-flow-modified Bardenpho process receiving wastewater from both municipal and industrial origins. As a result, ARW was found to have a direct effect on bulking in secondary clarifiers and foaming in anaerobic digesters (AD) despite its relatively small flow rate. During the cut-off period a highly stable sludge volume index at 80 mL g−1 level was obtained in the secondary clarifiers, effluent suspended solids concentration was reduced and continuous feeding to AD was recovered. Sludge density increased in the thickeners during hot season. Secondary clarifiers showed good and stable settleability despite low dissolved oxygen, food/microorganism ratio and high sludge retention time and ammonium levels in the biological unit. The bulking and foaming effect was presented on the plant's internal flow balance. ARW needs serious consideration for elimination by appropriate technologies because of its high potential as a multi-dimensional pollutant source, not only as a carrier of nutrients but also as a possible carrier of filamentous bacteria, which might promote chronic seeding and retention in the system.

scholarly journals 443 Nonplanar Vibration of a Cantilevered Pipe due to an Internal Flow : The Effects of Horizontal Excitation at the Upper End

2003 ◽  
Vol 2003 (0) ◽  
pp. _443-1_-_443-6_
Author(s):  
Kiyotaka YAMASHITA ◽  
Jun AGATA ◽  
Masatsugu YOSHIZAWA
Keyword(s):  
Internal Flow ◽  
Nonplanar Vibration ◽  
Cantilevered Pipe

Internal flow effect on the cross-flow vortex-induced vibration of a cantilevered pipe discharging fluid

2017 ◽  
Vol 137 ◽  
pp. 120-128 ◽  
Author(s):  
Shuai Meng ◽  
Hiroyuki Kajiwara ◽  
Weijing Zhang
Keyword(s):  
Cross Flow ◽  
Internal Flow ◽  
Vortex Induced Vibration ◽  
Flow Effect ◽  
Cantilevered Pipe ◽  
The Cross ◽  
Flow Vortex
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