scholarly journals ENERGY AND TURBULENT WIND FLOW CHARACTERISTICS IN THE BUILT ENVIRONMENT

2015 ◽  
Vol 37 (2) ◽  
pp. 20-31
Author(s):  
V. G. Novikov
Keyword(s):  
Numerical Modeling ◽  
Wind Power ◽  
Power Supply ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Transport Processes ◽  
Wind Flow ◽  
Target Area ◽  
Turbulent Wind ◽  
Power Installations

Presented the results of numerical modeling of transport processes in the interaction of wind flow in the surface layer of the atmosphere with the buildings and structures located within the compact urban development. In the target area calculated three-dimensional velocity field of wind power density of the wind flow and turbulence characteristics in order to determine the most appropriate places of location of wind power installations for power supply pilot house passive type.  

scholarly journals Modeling and Computation of Flow in a Passage With 360° Turning and Multiple Airfoils

1991 ◽  
Author(s):  
W. Shyy ◽  
T. C. Vu
Keyword(s):  
Porous Medium ◽  
Numerical Modeling ◽  
Detailed Analysis ◽  
Flow Condition ◽  
Global Analysis ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Hydraulic Turbine ◽  
The Individual ◽  
Spiral Casing

Numerical modeling of the three-dimensional flows in a spiral casing of a hydraulic turbine, containing a passage of 360-degree turning and multiple elements of airfoils (the so-called distributor), is made. The physical model is based on a novel two-level approach, comprising of (1) a global model that adequately accounts for the geometry of the spiral casing but smears out the details of the distributor and represents the multiple airfoils by a porous medium treatment, and (2) a local model that performs detailed analysis of flow in the distributor region. The global analysis supplies the inlet flow condition for the individual cascade of distributor airfoils, while the distributor analysis yields the information needed for modeling the characteristics of the porous medium. Comparisons of pressure and velocity profiles between measurement and prediction have been made to assess the validity of the present approach. Flow characteristics in the spiral casing are also discussed.

scholarly journals Evaluation of Wind Flow Characteristics by RANS-Based Numerical Site Calibration (NSC) Method with Met-Tower Measurements and Its Application to a Complex Terrain

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5121 ◽  
Author(s):  
Jae-ho Jeong ◽  
Kwangtae Ha
Keyword(s):  
High Resolution ◽  
Wind Turbine ◽  
Complex Terrain ◽  
Cfd Simulation ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Vortical Flow ◽  
Wind Flow ◽  
Rans Simulation ◽  
Resolution Scheme

The performance of wind turbines is not only dependent on the wind turbine design itself, but is also dependent on the accurate assessment of wind resources at the installation site. In this paper, the numerical site calibration (NSC) method using three-dimensional Reynolds-averaged Navier–Stokes (RANS) simulation was proposed to accurately forecast the wind flow characteristics of wind turbine sites with complex terrains, namely Methil in Scotland, and Haenam in South Korea. From NSC at the Methil and Haenam sites, it was shown that the complicated and vortical flow fields around hills and valleys were captured using the three-dimensional RANS CFD simulation in Ansys CFX software based on a high-resolution scheme with a renormalization group (RNG)-based k-ε turbulence model. It was also shown that topographically induced wind profile and turbulence intensity over a local-scale complex terrain are remarkably dominated by flow separation after passing hills. It was concluded that the proposed NSC method using three-dimensional RANS simulation with a high-resolution scheme was an economically useful method for evaluating wind flow characteristics numerically to assess wind turbine sites with complex terrains and designing the wind farm layout.

Modeling of Airflow in the Pharynx With Application to Sleep Apnea

1998 ◽  
Vol 120 (3) ◽  
pp. 416-422 ◽  
Author(s):  
B. Shome ◽  
L.-P. Wang ◽  
M. H. Santare ◽  
A. K. Prasad ◽  
A. Z. Szeri ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Sleep Apnea ◽  
Pressure Drop ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Transitional Flow ◽  
Subtle Change ◽  
Onset Of Turbulence ◽  
Wide Range ◽  
Sleep Apnea Treatment

A three-dimensional numerical modeling of airflow in the human pharynx using an anatomically accurate model was conducted. The pharynx walls were assumed to be passive and rigid. The results showed that the pressure drop in the pharynx lies in the range 200-500 Pa. The onset of turbulence was found to increase the pressure drop by 40 percent. A wide range of pharynx geometries covering three sleep apnea treatment therapies (CPAP, mandibular repositioning devices, and surgery) were modeled and the resulting flow characteristics were investigated and compared. The results confirmed that the airflow in the pharynx lies in the laminar-to-turbulence transitional flow regime and thus, a subtle change in the morphology caused by these treatment therapies can significantly affect the airflow characteristics.

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