scholarly journals A new formula based on computational fluid dynamics for estimating maximum depth of scour by jets from overflow dams

2014 ◽  
Vol 16 (5) ◽  
pp. 1210-1226 ◽  
Author(s):  
Sherong Zhang ◽  
Bohui Pang ◽  
Gaohui Wang
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Maximum Velocity ◽  
Maximum Depth ◽  
Scour Depth ◽  
Absolute Deviation ◽  
Scour Hole ◽  
Computational Fluid Dynamics Cfd ◽  
New Formula ◽  
Lm Algorithm

The prediction of the maximum depth of the scour hole formed downstream of overflow dams is critical in determining the safety of hydraulic structures. Most of the conventional formulae are not able to consider complex hydraulic and morphologic conditions. A new formula for estimating the maximum depth of the scour hole based on computational fluid dynamics (CFD), which can be used to simulate the complicated phenomenon, is proposed. The relationship between the maximum velocity in numerical simulations and the maximum scour depth is reflected in this formula, which is established using the Levenberg–Marquardt (LM) algorithm. The validity of this proposed formula is discussed by comparing this formula with three other conventional formulae. The prediction formula based on CFD is applied to the Wuqiangxi Dam, and the absolute deviation of the predicted maximum scour depth (35.44 m) from the measured depth (36.00 m) is 0.56 m.

Comparison Final Velosity Between Sailing Boat With a Rigid Airfoil and Cloth Sail

2006 ◽  
Author(s):  
H. Amini ◽  
M. Rad ◽  
A. Fakhraee
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Maximum Velocity ◽  
Design Tools ◽  
Hydrodynamic Calculation ◽  
Velocity Prediction ◽  
Computational Fluid Dynamics Cfd ◽  
Hull Forms ◽  
Sailing Boat ◽  
Experimental Equation

The powering requirement of a ship is one of the most important aspects of naval architecture. Traditionally, ships have been tested for hull resistance using hydrodynamic tank testing. But it is very time consuming, expensive, and has inherent scaling errors. Because of these reasons, today many vessels are sold on the market without any model testing. Another set of design tools are Computational Fluid Dynamics and parametric prediction. Computational Fluid Dynamics (CFD) codes are not yet wholly proven in its accuracy. Parametric predictions contain acquired data for a specific family of hull forms and use key hull parameters to evaluate a particular design. This tool is absolutely validating. In this work, parametric predictions tool has been used for velocity prediction of sailing boats and experimental equation has been used for hydrodynamic and aerodynamic calculation. However in this work from experimental equation from Delft towing tank has been used for hydrodynamic calculation but it is acceptable for more boats and ships. In this work velocity is predicted for a sailing boat with one rigid airfoil and sailing boat with cloth sailing. Rigid airfoil can control the velocity of boat. The maximum velocity occurred in 70 to 120 degree angle of courses. In Final stage, the velocity of boat is compared between sailing boat with rigid airfoil and cloth sail.

The Impact of Relative Position of the High-Rise Buildings on the Wind Flow

2016 ◽  
Vol 820 ◽  
pp. 320-325 ◽  
Author(s):  
Dagmara Čeheľová ◽  
Milan Janák ◽  
Boris Bielek
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Maximum Velocity ◽  
Flow Section ◽  
Wind Flow ◽  
High Rise ◽  
Venturi Effect ◽  
Wind Velocities ◽  
Computational Fluid Dynamics Cfd ◽  
The Impact

The Venturi effect has been defined as the increase in fluid speed or flow rate due to a decrease of the flow section. In the present paper the wind speed conditions in passages between triangular buildings with different distances are studied with Computational Fluid Dynamics (CFD) to investigate the extent to which the Venturi effect is present in the passages. In this paper are considered eight different variants of relative positions of the two high-rise buildings. The variable is a distance between towers. They are investigated maximum wind velocities and the point at which the maximum velocity occurs for each from these variants.

Efficiency prediction for storage chambers using computational fluid dynamics

1996 ◽  
Vol 33 (9) ◽  
pp. 163-170 ◽  
Author(s):  
Virginia R. Stovin ◽  
Adrian J. Saul
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Shear Stress ◽  
Particle Tracking ◽  
Critical Value ◽  
Complex Geometries ◽  
Bed Shear Stress ◽  
Breadth Ratio ◽  
Computational Fluid Dynamics Cfd ◽  
Simulated Flow

Research was undertaken in order to identify possible methodologies for the prediction of sedimentation in storage chambers based on computational fluid dynamics (CFD). The Fluent CFD software was used to establish a numerical model of the flow field, on which further analysis was undertaken. Sedimentation was estimated from the simulated flow fields by two different methods. The first approach used the simulation to predict the bed shear stress distribution, with deposition being assumed for areas where the bed shear stress fell below a critical value (τcd). The value of τcd had previously been determined in the laboratory. Efficiency was then calculated as a function of the proportion of the chamber bed for which deposition had been predicted. The second method used the particle tracking facility in Fluent and efficiency was calculated from the proportion of particles that remained within the chamber. The results from the two techniques for efficiency are compared to data collected in a laboratory chamber. Three further simulations were then undertaken in order to investigate the influence of length to breadth ratio on chamber performance. The methodology presented here could be applied to complex geometries and full scale installations.

Improvement of real-scale raceway bioreactors for microalgae production using Computational Fluid Dynamics (CFD)

2021 ◽  
Vol 54 ◽  
pp. 102207
Author(s):  
Cristian Inostroza ◽  
Alessandro Solimeno ◽  
Joan García ◽  
José M. Fernández-Sevilla ◽  
F. Gabriel Acién
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Computational Fluid Dynamics Cfd ◽  
Real Scale

scholarly journals Design of Novel Flash Ironmaking Reactors for Greatly Reduced Energy Consumption and CO2 Emissions

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 332
Author(s):  
Hong Yong Sohn ◽  
De-Qiu Fan ◽  
Amr Abdelghany
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Large Diameter ◽  
Reduction Reaction ◽  
The Novel ◽  
Height Ratio ◽  
Fine Iron ◽  
Computational Fluid Dynamics Cfd ◽  
High Reduction ◽  
Iron Ore Concentrate

The development of a novel ironmaking technology based on fine iron ore concentrate in a flash reactor is summarized. The design of potential industrial reactors for flash ironmaking based on the computational fluid dynamics technique is described. Overall, this simulation work has shown that the size of the reactor used in the novel flash ironmaking technology (FIT) can be quite reasonable vis-à-vis the blast furnaces. A flash reactor of 12 m diameter and 35 m height with a single burner operating at atmospheric pressure would produce 1.0 million tons of iron per year. The height can be further reduced by either using multiple burners, preheating the feed gas, or both. The computational fluid dynamics (CFD)-based design of potential industrial reactors for flash ironmaking pointed to a number of features that should be incorporated. The flow field should be designed in such a way that a larger portion of the reactor is used for the reduction reaction but at the same time excessive collision of particles with the wall must be avoided. Further, a large diameter-to-height ratio that still allows a high reduction degree should be used from the viewpoint of decreased heat loss. This may require the incorporation of multiple burners and solid feeding ports.

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