Modelling Transport and Dispersion of Effluent Outfalls

1992 ◽  
Vol 25 (9) ◽  
pp. 143-154 ◽  
Author(s):  
A. J. Monteiro ◽  
R. J. Neves ◽  
E. R. Sousa
Keyword(s):  
Velocity Field ◽  
Variable Thickness ◽  
Near Field ◽  
Hydrodynamical Model ◽  
Lagrangian Model ◽  
Far Field ◽  
Initial Thickness ◽  
High Concentration ◽  
Concentration Gradients ◽  
Model Based

The accuracy, applicability and limitations of several kinds of models to simulate the dispersion processes are discussed. An Eulerian-lagrangian model based on the advection of particles is presented. This model is particularly adequate to study plumes with high concentration gradients like those developed by outfall discharges. The model uses the velocity field computed by a 2D depth-integrated hydrodynamical model. The linkage of the near and far field solutions is taken into account using particles of variable thickness. The initial thickness is estimated using an empiric relation for the near field depending on the local discharge conditions. Some results are presented and discussed.

Boundary-Integral Representation of Linear Free-Surface Potential Flows

1997 ◽  
Vol 41 (01) ◽  
pp. 10-16
Author(s):  
Francis Noblesse ◽  
Chi Yang ◽  
Xiao-Bo Chen
Keyword(s):  
Velocity Field ◽  
Potential Flow ◽  
Near Field ◽  
Boundary Surface ◽  
Flow Region ◽  
Numerical Differentiation ◽  
Boundary Integral ◽  
Diffraction Radiation ◽  
Linear Potential ◽  
Far Field

A new potential-flow representation, which defines the velocity field ∇ϕ in a potential flow region explicitly in terms of the velocity distribution (u,v,w) at a boundary surface E, is given for the case of wave diffraction-radiation by a ship. This flow representation does not involve the potential ϕ at ϵ (unlike the usual Green identity which expresses ϕ within a flow domain in terms of boundary values of ϕ and ∂ϕ/∂n) and defines the velocity field ∇ϕ directly (i.e., not via numerical differentiation of ϕ). The new flow representation can be useful for extending a given near-field flow into the far field, and for coupling a near-field nonlinear viscous flow calculation method and a far-field linear potential-flow representation.

scholarly journals An Improved Equivalent Dipole Moment Source Model Based on Regularization Optimization Method for Near Field-Far Field Conversion

IEEE Access ◽  
2020 ◽  
Vol 8 ◽  
pp. 42504-42518
Author(s):  
Wei Liu ◽  
Zhaowen Yan ◽  
Jianwei Wang ◽  
Zheng Min ◽  
Zhangqiang Ma
Keyword(s):  
Dipole Moment ◽  
Near Field ◽  
Optimization Method ◽  
Source Model ◽  
Far Field ◽  
Model Based ◽  
Equivalent Dipole

Magnetic Tag Antenna for UHF Near-field and Far-Field RFID Applications

2015 ◽  
Vol 5 (2) ◽  
pp. 119
Author(s):  
Mondher Dhaouadi ◽  
M. Mabrouk ◽  
T. Vuong ◽  
A. Ghazel
Keyword(s):  
Near Field ◽  
Far Field ◽  
Rfid Applications

Far field modeling of the Mamala Bay outfalls

1998 ◽  
Vol 38 (10) ◽  
pp. 323-330
Author(s):  
Philip J. W. Roberts
Keyword(s):  
Field Model ◽  
Near Field ◽  
Far Field ◽  
Field Modeling ◽  
Visitation Frequency ◽  
Statistical Variation ◽  
Long Time ◽  
Harmonic Average ◽  
Ocean Outfall ◽  
Acoustic Doppler Current Profilers

The results of far field modeling of the wastefield formed by the Sand Island, Honolulu, ocean outfall are presented. A far field model, FRFIELD, was coupled to a near field model, NRFIELD. The input data for the models were long time series of oceanographic observations over the whole water column including currents measured by Acoustic Doppler Current Profilers and density stratification measured by thermistor strings. Thousands of simulations were made to predict the statistical variation of wastefield properties around the diffuser. It was shown that the visitation frequency of the wastefield decreases rapidly with distance from the diffuser. The spatial variation of minimum and harmonic average dilutions was also predicted. Average dilution increases rapidly with distance. It is concluded that any impact of the discharge will be confined to a relatively small area around the diffuser and beach impacts are not likely to be significant.

Direction of Arrival Estimation Under Near-Field Interference Using Matrix Filter

2015 ◽  
Vol 23 (04) ◽  
pp. 1540007 ◽  
Author(s):  
Guolong Liang ◽  
Wenbin Zhao ◽  
Zhan Fan
Keyword(s):  
Near Field ◽  
Direction Of Arrival ◽  
Doa Estimation ◽  
Direction Of Arrival Estimation ◽  
Far Field ◽  
Data Simulation ◽  
Estimation Algorithms ◽  
Simulation Results

Direction of arrival (DOA) estimation is of great interest due to its wide applications in sonar, radar and many other areas. However, the near-field interference is always presented in the received data, which may result in degradation of DOA estimation. An approach which can suppress the near-field interference and preserve the far-field signal desired by using a spatial matrix filter is proposed in this paper and some typical DOA estimation algorithms are adjusted to match the filtered data. Simulation results show that the approach can improve capability of DOA estimation under near-field inference efficiently.

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