Three-Dimensional Computational Hydrodynamics Modeling for Algae Transport and Growth

2017 ◽  
Author(s):  
Haidong Liu ◽  
Zhongquan Charlie Zheng ◽  
Bryan Young
Keyword(s):  
Green Algae ◽  
Hydrodynamic Model ◽  
Algal Blooms ◽  
Stokes Equations ◽  
Transport Model ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Fractional Step Method ◽  
Blue Green Algae

In this study, a three-dimensional model coupling hydrodynamics with algae transport dynamics is investigated. The hydrodynamic model solves the three-dimensional Navier-Stokes equations by a semi-implicit, fractional step method, where the hydrostatic components are determined first and the non-hydrostatic pressure and other components are determined in a subsequent step. Wind velocity on the water surface is accounted for the effect of wind stress on the flow velocities in the hydrodynamic model. Then, the model is coupled with an algae transport model, which enables simulation of algae transport and algal blooms. As an example, the model is implemented to analyze the transition of blue-green algae in Milford Lake, which is the largest man-made lake in Kansas suffering from blue-green algae blooms. The three-dimensional model provides a robust and efficient way for hydrodynamic and algae modeling and can be implemented to studies on different types of rivers and reservoirs easily. The simulated results can be very useful for algae control and prediction in both short and long terms.

Simulating the Behaviour and Fate of an Oil Spill Using a Coupled Three-Dimensional Hydrodynamic Model

2014 ◽  
Vol 2014 (1) ◽  
pp. 901-918
Author(s):  
James A. Stronach ◽  
Aurelien Hospital
Keyword(s):  
Oil Spill ◽  
Hydrodynamic Model ◽  
Three Dimensional ◽  
Local Network ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Near Surface ◽  
Water Properties ◽  
Response Planning ◽  
The Impact

ABSTRACT Oil behavior and fate have been simulated extensively by several spill models. These simulations can be greatly enhanced by the use of a coupled three-dimensional model of currents and water properties to determine oil transport and weathering, both on the water surface and in the water column. Several physical and chemical processes such as vertical dispersion in response to wave action, resurfacing when waves die down, sinking through loss of volatiles and dissolution are essential in assessing the impact of an oil spill on the environment. Dissolution is especially important, considering the known toxicity of several of the constituents of liquid hydrocarbons. For this study, a three-dimensional hydrodynamic model of coastal British Columbia was coupled to an oil trajectory and weathering model in order to simulate the complete fate and behaviour of surface, shoreline-retained, dissolved, sunken and dispersed oil. Utilization of a three-dimensional model is the key to adequately modelling the transport of a spill in an estuarine region such as in the Strait of Georgia, B.C., where the distribution of currents and water properties is strongly affected by estuarine processes: the Fraser River enters at the surface and oceanic waters from the Pacific enter as a deep inflow. Three-dimensional currents and water properties were provided by the hydrodynamic model, H3D, a semi-implicit model using a staggered Arakawa grid and variable number of layers in the vertical direction to resolve near-surface processes. Waves were simulated using the wave model SWAN. Winds were obtained from the local network of coastal light stations and wind buoys. Stochastic modelling was conducted first, using only surface currents, to determine probabilistic maps of the oil trajectory on water and statistical results were extracted, such as the amount of shoreline oiled and the amount of oil evaporated, both for the ensemble of simulations constituting the stochastic simulation, as well as for any particular individual simulation. Deterministic scenarios were then selected and the fate of the oil, such as the dissolved and sunken fractions, was tracked over a 14 day period on the three-dimensional grid. This method has been used for environmental impact assessment and spill response planning.

Comparison of a Multi-Dimensional Model With a Reduced Order Pseudo Three-Dimensional Model for Simulation of Solid Oxide Fuel Cells

2006 ◽  
Author(s):  
Suryanarayana Pakalapati ◽  
Ibrahim Yavuz ◽  
Francisco Elizalde-Blancas ◽  
Ismail Celik ◽  
Mehrdad Shahnam
Keyword(s):  
Fuel Cell ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Reduced Order Modeling ◽  
Navier Stokes ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Reduced Order ◽  
Three Dimensional Models ◽  
Commercial Solver

Numerical modeling has helped the SOFC research for over a decade in which period the models grew in complexity and detail. Multi-dimensional detailed models such as FLUENT’s SOFC module calculate three dimensional distributions of velocity, temperature, concentration and electric potential inside all components of the fuel cell. Such models while being very helpful in understanding the processes inside the fuel cell may prove to be very expensive for transient simulations and simulations of multi-cell stacks. Hence reduced order modeling is still used for such applications. However, reduced order modeling entails reduction of detail and consequent loss in accuracy. In this paper a multi-dimensional SOFC code, FLUENT’s SOFC module, is compared with a reduced order pseudo three-dimensional model, DREAM SOFC. FLUENT’s SOFC module is a commercial solver built on the popular CFD solver FLUENT. DREAM SOFC is an in house code developed at Computational Fluid Dynamics and Applied Multi Physics (CFD&AMP) Center at West Virginia University. It is a combination of a one dimensional model for channels and three-dimensional models for the rest of the components in a SOFC. This approach avoids having to solve Navier-Stokes equations inside channels but still retains the three-dimensionality inside important components. Same test cases with similar conditions are simulated with these codes and results are compared with each other.

scholarly journals Potential impact of iodinated replacement compounds CF<sub>3</sub>I and CH<sub>3</sub>I on atmospheric ozone: a three-dimensional modeling study

2010 ◽  
Vol 10 (20) ◽  
pp. 10129-10144 ◽  
Author(s):  
D. Youn ◽  
K. O. Patten ◽  
D. J. Wuebbles ◽  
H. Lee ◽  
C.-W. So
Keyword(s):  
Transport Model ◽  
Stratospheric Ozone ◽  
Vertical Mixing ◽  
Three Dimensional ◽  
Convective Transport ◽  
Atmospheric Ozone ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Model Calculations ◽  
The Tropics

Abstract. The concept of Ozone Depletion Potentials (ODPs) is extensively used in policy considerations related to concerns about the effects of various halocarbons and other gases on stratospheric ozone. Many of the recent candidate replacement compounds have atmospheric lifetimes shorter than one year in order to limit their environmental effects, especially on stratospheric ozone. Using a three-dimensional global chemistry-transport model (CTM) of the troposphere and the stratosphere, the purpose of this study is to evaluate the potential effects of several very short-lived iodinated substances, namely iodotrifluoromethane (CF3I) and methyl iodide (CH3I), on atmospheric ozone. Like other chemicals with extremely short lifetimes, the stratospheric halogen loading and resulting ozone effects from these compounds are strongly dependent on the location of emissions. For CF3I, a possible replacement candidate for bromotrifluoromethane (CF3Br), ODPs derived by the three-dimensional model are 0.008 with chemical lifetime of 5.03 days and 0.016 with a lifetime of 1.13 days for emissions assumed to be evenly distributed over land surfaces at mid-latitudes and the tropics, respectively. While this is the first time the ODPs have been evaluated with a three-dimensional model, these values are in good agreement with those derived previously. The model calculations suggest that tropical convection could deliver a larger portion of the gas and their breakdown products to the upper troposphere and lower stratosphere if emission source is located in the tropics. The resulting ODP for CH3I, emitted from mid-latitudes, is 0.017 with lifetime of 13.59 days. Valid simulations of convective transport, vertical mixing and degradation chemistry of CH3I are shown that have good qualitative agreement between the model derived distribution of background CH3I, based on global source emission fluxes from previous studies, and available observations especially in vertical profiles.

scholarly journals Potential impact of iodinated replacement compounds CF<sub>3</sub>I and CH<sub>3</sub>I on atmospheric ozone: a three-dimensional modeling study

2010 ◽  
Vol 10 (7) ◽  
pp. 16659-16690
Author(s):  
◽  
K. O. Patten ◽  
D. J. Wuebbles ◽  
◽  
Keyword(s):  
Transport Model ◽  
Stratospheric Ozone ◽  
Three Dimensional ◽  
Atmospheric Ozone ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Model Calculations ◽  
Three Dimensional Modeling ◽  
Land Surfaces ◽  
The Tropics

Abstract. The concept of Ozone Depletion Potentials (ODPs) is extensively used in policy considerations related to concerns about the effects of various halocarbons and other gases on stratospheric ozone. Many of the recent candidate replacement compounds have atmospheric lifetimes shorter than one year in order to limit their environmental effects, especially on stratospheric ozone. Using a three-dimensional global chemistry-transport model (CTM) of the troposphere and the stratosphere, the purpose of this study is to evaluate the potential effects of several very short-lived iodinated substances, namely iodotrifluoromethane (CF3I) and methyl iodide (CH3I), on atmospheric ozone. Like other chemicals with extremely short lifetimes, the stratospheric halogen loading and resulting ozone effects from these compounds are strongly dependent on the location of emissions. For CF3I, a possible replacement candidate for bromotrifluoromethane (CF3Br), ODPs derived by the three-dimensional model are 0.008 with chemical lifetime of 5.03 days and 0.016 with a lifetime of 1.13 days for emissions assumed to be evenly distributed over land surfaces at mid-latitudes and the tropics, respectively. While this is the first time the ODPs have been evaluated with a three-dimensional model, these values are in good agreement with those derived previously. The model calculations suggest that tropical convection could deliver a larger portion of the gas and their breakdown products to the upper troposphere and lower stratosphere if emission source is located in the tropics. The resulting ODP for CH3I, emitted from mid-latitudes, is 0.017 with lifetime of 13.59 days. The validity of our model iodine chemistry to evaluate ODPs of the iodine species is guaranteed with good qualitative agreement between the model derived distribution of background CH3I, based on global source emission fluxes from previous studies, and available observations especially in vertical profiles.

Freeze-Fracture Replication in the Ultrastructure of Blue-Green Algae

1967 ◽  
Vol 25 ◽  
pp. 74-75
Author(s):  
L. V. Leak
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Green Algae ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Electron Microscopic ◽  
Photosynthetic Membranes ◽  
Blue Green Algae ◽  
Cell Biol ◽  
Cellular Components

Electron microscopic observations of freeze-fracture replicas of Anabaena cells obtained by the procedures described by Bullivant and Ames (J. Cell Biol., 1966) indicate that the frozen cells are fractured in many different planes. This fracturing or cleaving along various planes allows one to gain a three dimensional relation of the cellular components as a result of such a manipulation. When replicas that are obtained by the freeze-fracture method are observed in the electron microscope, cross fractures of the cell wall and membranes that comprise the photosynthetic lamellae are apparent as demonstrated in Figures 1 & 2.A large portion of the Anabaena cell is composed of undulating layers of cytoplasm that are bounded by unit membranes that comprise the photosynthetic membranes. The adjoining layers of cytoplasm are closely apposed to each other to form the photosynthetic lamellae. Occassionally the adjacent layers of cytoplasm are separated by an interspace that may vary in widths of up to several 100 mu to form intralamellar vesicles.

Three-Dimensional Model for Virtual Surgical Simulation, during Complex Skull Base Surgery and Aneurysm Surgery

Skull Base ◽  
2008 ◽  
Vol 18 (S 01) ◽  
Author(s):  
Akio Morita ◽  
Toshikazu Kimura ◽  
Shigeo Sora ◽  
Kengo Nishimura ◽  
Hisayuki Sugiyama ◽  
...  
Keyword(s):  
Skull Base ◽  
Surgical Simulation ◽  
Skull Base Surgery ◽  
Three Dimensional ◽  
Aneurysm Surgery ◽  
Dimensional Model ◽  
Three Dimensional Model
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