Application Of CFD Modelling Research Articles

IRREGULAR WAVE MODELLING WITH CFD IN SULAFJORD FOR THE E39 PROJECT

The E39 project aims at building a continuous ferry-free coastal highway along the west coast of Norway. Sulafjord is one of the fjords where ferries are to be replaced with floating bridges or floating tunnels. The floating structures demand accurate and realistic numerical simulations of the wave propagation and transformation in the fjords. The Norwegian coastline is characterized by dramatic water depth changes and deep water conditions. The coastal water also contains both swells and local wind-generated waves. These conditions, along with series of islands outside the fjords and very irregular coastline, make wave modeling more challenging for this region. Thus, the application of CFD models which provide high-resolution and phase-resolved solutions for complicated wave freesurface is explored. First, the spectral wave model SWAN is used to estimate the wave properties at the inlet of the Sulafjord from offshore wave data. Using the estimated wave data at the inlet as input, a large-scale 3D regular wave CFD simulation is performed using the open-source model REEF3D. Then unidirectional and multi-directional irregular wave CFD simulations are performed to represent a more realistic sea state, using a frequency spectra and a directional spreading function. The statistical properties of the simulated irregular ocean waves at three locations inside the fjord are compared among the CFD simulations and with the spectral wave model. The differences in the simulation results are discussed and studied.

Application of CFD Model in Analyzing the Performance of a Liquid Desiccant Dehumidifier

The dehumidifier of a liquid desiccant air conditioning system was the research object of present paper. A model was established on the basis of CFD. The interior heat and mass transfer processes were simulated with the model. Intensive analysis was conducted to investigate the influence of some factors, including the inlet desiccant temperature, desiccant flow rate and internally cooling.

Temperature Field-Wind Velocity Field Optimum Control of Greenhouse Environment Based on CFD Model

The computational fluid dynamics technology is applied as the environmental control model, which can include the greenhouse space. Basic environmental factors are set to be the control objects, the field information is achieved via the division of layers by height, and numerical characteristics of each layer are used to describe the field information. Under the natural ventilation condition, real-time requirements, energy consumption, and distribution difference are selected as index functions. The optimization algorithm of adaptive simulated annealing is used to obtain optimal control outputs. A comparison with full-open ventilation shows that the whole index can be reduced at 44.21% and found that a certain mutual exclusiveness exists between the temperature and velocity field in the optimal course. All the results indicate that the application of CFD model has great advantages to improve the control accuracy of greenhouse.

Wind Flow Conditions in Offshore Wind Farms: Validation and Application of a CFD Wake Model

AbstractSince August 2009, the first German offshore wind farm ‘alpha ventus’ is operating close to the wind measurement platform FINO1. Within the research project RAVE-OWEA the wind flow conditions in ‘alpha ventus’ were assessed in detail, simulated with a CFD wake model and compared with the measurements. Wind data measured at FINO1 have been evaluated for wind speed reduction and turbulence increase in the wake. Additionally operational data were evaluated for the farm efficiency. The atmospheric stability has been evaluated by temperature measurements of air and water and the impact of atmospheric stability on the wind conditions in the wake has been assessed. As an application of CFD models the generation of power matrices is introduced. Power matrices can be used for the continual monitoring of the single wind turbines in the wind farm. A power matrix based on CFD simulations has been created for ‘alpha ventus’ and tested against the measured data.

Evaluation of Thermal Comfort in Indoor Stadiums of the Athens 2004 Olympic Games with CFD Models: Case of Nikea Indoor Stadium

The Athens 2004 Olympic Games were completed successfully in open and indoor stadiums in Greece. Prior to the Games, the Ministry of Culture launched a study on the evaluation and improvement of the indoor conditions safety, air quality, and comfort in the newly developed sports arena complexes and stadiums for Athens 2004. This study was performed with the use of Computational Fluid Dynamics CFD models. CFD models have been increasingly used in the last 15–20 years to evaluate comfort conditions thermal and draught , smoke conditions, and indoor air quality. There is a considerable amount of research work dealing with the application of CFD models in indoor environments, mainly offices and residential areas. However, there are only a few published studies in indoor stadiums with either CFD models or experimental techniques. For example, Nishioka et al. 2000 performed measurements to evaluate the indoor thermal environments in a large domed stadium in Japan, which was built mainly for professional baseball games. CFD modeling was performed in the Yoyogi National Stadium in Tokyo FLUENT 2001 and the Olympic ice hockey stadium in Turin Chown et al. 2006 . The Yoyogi National Stadium was constructed in Tokyo for the Olympic Games of 1964. Since the Olympics, the stadium has continued to be used for swimming competitions, but has also been used as a concert hall. A CFD evaluation of the stadium interior was performed to better understand the quality of the air-conditioning system for both modes of stadium operation. In the Olympic ice hockey stadium in Turin, a CFD study was performed to evaluate fire hazards in the stadium by reviewing smoke conditions in the arena for various scenarios and uses, i.e. Olympic or concert modes. In the present work, a CFD model is used to calculate airflow velocities and temperatures in Nikea Indoor Stadium, which hosted weightlifting during the Athens Games. The calculated ve-

NUMERICAL RESEARCH ON A SPECIAL FLUID PHENOMENON: RANQUE-HILSCH EFFECT

An application of CFD model for the simulation of a strongly swirling and high speed flow in the vortex tube is presented in this paper. A partly modified standard K-ε turbulent model has been used to investigate the flow characteristics and energy separation effect in the vortex tube. It is found that there is an obvious energy separation effect in the vortex tube and the numerical solutions of the flow and temperature fields agree well with the experiments. More detailed flow features are obtained by the CFD calculation. Based on the validated numerical model, the influence of the cold flow fraction on the energy separation effect is also investigated and compared with experimental results.

Modeling and simulating engineering processes with computational fluid dynamics

processes and to demonstrate how CFD is helping to better understand the fundamentals of a wide variety of engineering processes. The articles discuss the development and application of CFD models to simulate engineering problems in many processing industries including surface engineering, metal casting, glass, polymers, MEMS, and