A Numerical Model for the Quantification of Light/Dark Cycles in Microalgal Cultures: Air-Lift and Bubble-Column Photobioreactor Analysis by Means of Computational Fluid Dynamics

2015 ◽  
Vol 48 (1) ◽  
pp. 61-71 ◽  
Author(s):  
Luca Giannelli ◽  
Hideki Yamaji ◽  
Tomohisa Katsuda
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Model ◽  
Bubble Column ◽  
Bubble Column Photobioreactor ◽  
Air Lift

Validation of a Computationally Efficient Computational Fluid Dynamics (CFD) Model for Industrial Bubble Column Bioreactors

2014 ◽  
Vol 53 (37) ◽  
pp. 14526-14543 ◽  
Author(s):  
Dale D. McClure ◽  
Hannah Norris ◽  
John M. Kavanagh ◽  
David F. Fletcher ◽  
Geoffrey W. Barton
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Bubble Column ◽  
Cfd Model ◽  
Computationally Efficient ◽  
Computational Fluid Dynamics Cfd

Validation of a Numerical Model for the Investigation of Tension Leg Platforms With Marine Energy Application Using REEF3D

2021 ◽  
Author(s):  
Christian Windt ◽  
Nils Goseberg ◽  
Tobias Martin ◽  
Hans Bihs
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Model ◽  
Numerical Modelling ◽  
Numerical Data ◽  
Wave Structure ◽  
Offshore Wind ◽  
High Resolution Data ◽  
Marine Energy ◽  
Mooring Dynamics

Abstract Exploiting the offshore wind resources using floating offshore wind systems at sites with deep water depths requires advanced knowledge of the system behaviour, including the hydro-, areo-, and mooring dynamics. To that end, high-fidelity numerical modelling tools, based on Computational Fluid Dynamics, can support the research and development of floating offshore wind systems by providing high-resolution data sets. This paper presents the first steps towards the numerical modelling of tension leg platforms for floating offshore wind applications using the open-source Computational Fluid Dynamics toolbox REEF3D. The numerical model of a taut-moored structure is validated against experimental reference data. Results from wave-only test cases highlight the simplicity and effectiveness of the wave generation method, implemented in REEF3D. For the considered wave-structure interaction cases, deviations between the experimental and numerical data can be observed for the surge and pitch displacements, while the heave displacement and the mooring forces are capture with sufficient accuracy. Overall, the numerical results indicate high potential of REEF3D to be used for the modelling of floating offshore wind systems.

scholarly journals Numerical model of self-propulsion in a fluid

2005 ◽  
Vol 2 (2) ◽  
pp. 79-88 ◽  
Author(s):  
D.J.J Farnell ◽  
T David ◽  
D.C Barton
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Model ◽  
Lateral Displacement ◽  
Leading Edge ◽  
Mechanical Device ◽  
Lagrange Equations ◽  
Weakly Coupled

We provide initial evidence that a structure formed from an articulated series of linked elements, where each element has a given stiffness, damping and driving term with respect to its neighbours, may ‘swim’ through a fluid under certain conditions. We derive a Lagrangian for this system and, in particular, we note that we allow the leading edge to move along the x -axis. We assume that no lateral displacement of the leading edge of the structure is possible, although head ‘yaw’ is allowed. The fluid is simulated using a computational fluid dynamics technique, and we are able to determine and solve Euler–Lagrange equations for the structure. These two calculations are solved simultaneously by using a weakly coupled solver. We illustrate our method by showing that we are able to induce both forward and backward swimming. A discussion of the relevance of these simulations to a slowly swimming body, such as a mechanical device or a fish, is given.

Inlet Losses in Counterflow Wet-Cooling Towers

2001 ◽  
Vol 123 (2) ◽  
pp. 460-464 ◽  
Author(s):  
E. de Villiers ◽  
D. G. Kro¨ger
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Numerical Model ◽  
Loss Coefficient ◽  
Cooling Towers ◽  
Empirical Correlations ◽  
Dependent Variables ◽  
Loss Coefficients

The inlet loss coefficients for dry, isotropically packed, circular and rectangular counterflow cooling towers are determined experimentally and empirical correlations are formulated to fit this data. Computational fluid dynamics is used to investigate the dependence of the inlet loss coefficient on the rain zone characteristics. The rain zone generally dampens the inlet loss, but the coupling is indirect and involves a large number of dependent variables. The numerical model is validated by means of experimental data for dry towers and it is found that the degree of accuracy achieved for circular towers exceeds that for rectangular towers. Consequently, the correlation derived to predict this occurrence for circular towers can be applied more confidently than its rectangular counterpart.

Numerical Investigation of Dusts Removal from Tramway Surface by Street Vacuum Sweeper

2011 ◽  
Vol 236-238 ◽  
pp. 1619-1622 ◽  
Author(s):  
Bo Fu Wu ◽  
Jin Lai Men ◽  
Jie Chen
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Numerical Model ◽  
Pressure Drop ◽  
Removal Efficiency ◽  
Pressure Drops ◽  
Operational Safety ◽  
Airflow Field ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Method

In order to enhance the operational safety of tram vehicle and reduce the wear of guide wheels mounted on the vehicle, it is necessary to remove particles such as dusts and silts from tramway surface. The aim of this paper is to evaluate the effectiveness of street vacuum sweeper for sucking up dusts from tramway surface. A numerical model was developed based on dusts removal process. Under different pressure drops across the pickup head of the street vacuum sweeper, the flow field and dusts removal efficiency were analyzed with computational fluid dynamics (CFD) method. The numerical results show that a higher pressure drop can improve the airflow field in the pickup head and results in higher dusts removal efficiency, but higher pressure drop definitely need more energy. Therefore, a balance should be taken into consideration.

Annular Gap Bubble Column: Experimental Investigation and Computational Fluid Dynamics Modeling

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Giorgio Besagni ◽  
Gaël Raymond Guédon ◽  
Fabio Inzoli
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Regime ◽  
Bubble Column ◽  
Gas Holdup ◽  
Operating Conditions ◽  
Optical Probes ◽  
Annular Gap ◽  
Fiber Optical ◽  
Flow Visualizations

This paper investigates the countercurrent gas–liquid flow in an annular gap bubble column with a 0.24 m inner diameter by using experimental and numerical investigations. The two-phase flow is studied experimentally using flow visualizations, gas holdup measurements, and double fiber optical probes in the following range of operating conditions: superficial air velocities up to 0.23 m/s and superficial water velocities up to −0.11 m/s, corresponding to gas holdups up to 29%. The flow visualizations were used to observe the flow patterns and to obtain the bubble size distribution (BSD). The gas holdup measurements were used for investigating the flow regime transitions, and the double fiber optical probes were used to study the local flow phenomena. A computational fluid dynamics (CFD) Eulerian two-fluid modeling of the column operating in the bubbly flow regime is proposed using the commercial software ansys fluent. The three-dimensional (3D) transient simulations have been performed considering a set of nondrag forces and polydispersity. It is shown that the errors in the global holdup and in the local properties are below 7% and 16%, respectively, in the range considered.

scholarly journals Modelling a Biochemical Reaction with Computational Fluid Dynamics

2005 ◽  
Vol 3 (1) ◽  
Author(s):  
Sotos C. Generalis ◽  
Gregory M Cartland Glover
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Bubble Column ◽  
Reaction Model ◽  
Biochemical Reaction ◽  
Single Plane ◽  
Solids Concentration ◽  
Computational Fluid Dynamics Cfd ◽  
Specific Growth Rates ◽  
The Impact

Earlier investigations (Cartland Glover et al., 2004) into the use of computational fluid dynamics (CFD) for the modelling of gas-liquid and gas-liquid-solid flow allowed a simple biochemical reaction model to be implemented. A single plane mesh was used to represent the transport and reaction of molasses, the mould Aspergillus niger and citric acid in a bubble column with a height to diameter aspect ratio of 20:1. Two specific growth rates were used to examine the impact that biomass growth had on the local solids concentration and the effect this had on the local hydrodynamics of the bubble column.

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