hydrodynamic and thermal dispersion modelling of the … · hydrodynamic and thermal dispersion...
TRANSCRIPT
![Page 1: Hydrodynamic and Thermal Dispersion Modelling of the … · Hydrodynamic and Thermal Dispersion Modelling of the Effluent in a Coastal Channel . Ahmad Sana, sana@squ.edu.om. Sultan](https://reader031.vdocuments.mx/reader031/viewer/2022021716/5ce2653788c993ab258bc0df/html5/thumbnails/1.jpg)
Hydrodynamic and Thermal Dispersion Modelling of the Effluent in a Coastal Channel
Ahmad Sana, [email protected] Sultan Qaboos University, Oman
![Page 2: Hydrodynamic and Thermal Dispersion Modelling of the … · Hydrodynamic and Thermal Dispersion Modelling of the Effluent in a Coastal Channel . Ahmad Sana, sana@squ.edu.om. Sultan](https://reader031.vdocuments.mx/reader031/viewer/2022021716/5ce2653788c993ab258bc0df/html5/thumbnails/2.jpg)
Contents
• Motivation • Study area • Numerical model • Results and discussion • Conclusions
![Page 3: Hydrodynamic and Thermal Dispersion Modelling of the … · Hydrodynamic and Thermal Dispersion Modelling of the Effluent in a Coastal Channel . Ahmad Sana, sana@squ.edu.om. Sultan](https://reader031.vdocuments.mx/reader031/viewer/2022021716/5ce2653788c993ab258bc0df/html5/thumbnails/3.jpg)
Motivation • Various types of industrial plants discharge effluents to the sea. Generally an outfall structure is designed to keep minimum possible impact on the ambient water quality. • In the present situation the industrial plant is located in the proximity of a natural wadi channel connected to the sea forming a lagoon-like water body. • The high discharge of effluent with higher than the ambient temperature may cause thermal pollution along-with erosion in the channel (Q=13,500m3/hr =3.75m3/s, T = 40oC).
![Page 4: Hydrodynamic and Thermal Dispersion Modelling of the … · Hydrodynamic and Thermal Dispersion Modelling of the Effluent in a Coastal Channel . Ahmad Sana, sana@squ.edu.om. Sultan](https://reader031.vdocuments.mx/reader031/viewer/2022021716/5ce2653788c993ab258bc0df/html5/thumbnails/4.jpg)
Study Area
![Page 5: Hydrodynamic and Thermal Dispersion Modelling of the … · Hydrodynamic and Thermal Dispersion Modelling of the Effluent in a Coastal Channel . Ahmad Sana, sana@squ.edu.om. Sultan](https://reader031.vdocuments.mx/reader031/viewer/2022021716/5ce2653788c993ab258bc0df/html5/thumbnails/5.jpg)
Numerical model
Delft3D-FLOW is the module of Delft3D suite that provides the hydrodynamic basis for water quality computations. The main purpose is the two-dimensional (2D, depth averaged) and three-dimensional (3D) simulation of tidal and wind-driven flow by solving the unsteady hydrodynamic equations.
![Page 6: Hydrodynamic and Thermal Dispersion Modelling of the … · Hydrodynamic and Thermal Dispersion Modelling of the Effluent in a Coastal Channel . Ahmad Sana, sana@squ.edu.om. Sultan](https://reader031.vdocuments.mx/reader031/viewer/2022021716/5ce2653788c993ab258bc0df/html5/thumbnails/6.jpg)
Numerical model The main physical phenomena, which are accounted for in Delft3D-FLOW, are: • Coriolis force. • Turbulence model to account for the vertical
turbulent viscosity and diffusivity • Shear stress exerted by the turbulent flow on the
bottom based on a quadratic Chézy or Manning formula.
• Simulation of the thermal discharge intake (advective-diffusion module).
• Simulation of drying and flooding of inter-tidal flats (moving boundaries)
![Page 7: Hydrodynamic and Thermal Dispersion Modelling of the … · Hydrodynamic and Thermal Dispersion Modelling of the Effluent in a Coastal Channel . Ahmad Sana, sana@squ.edu.om. Sultan](https://reader031.vdocuments.mx/reader031/viewer/2022021716/5ce2653788c993ab258bc0df/html5/thumbnails/7.jpg)
Computational Parameters ITEM
CONDITION
Simulation period August 7 to 21, 2009 Initial condition
Constant water temperature (25.6 oC)
Computational domain
Horizontal orthogonal curvilinear 206x21 with one layer (depth-averaged condition)
Boundary condition Predicted water level at open boundary (eastern boundary)
Meteorological data Uniform wind, air temperature, solar radiation and humidity from historical weather data
Bottom stress Colebrooke Equation
![Page 8: Hydrodynamic and Thermal Dispersion Modelling of the … · Hydrodynamic and Thermal Dispersion Modelling of the Effluent in a Coastal Channel . Ahmad Sana, sana@squ.edu.om. Sultan](https://reader031.vdocuments.mx/reader031/viewer/2022021716/5ce2653788c993ab258bc0df/html5/thumbnails/8.jpg)
Model domain
![Page 9: Hydrodynamic and Thermal Dispersion Modelling of the … · Hydrodynamic and Thermal Dispersion Modelling of the Effluent in a Coastal Channel . Ahmad Sana, sana@squ.edu.om. Sultan](https://reader031.vdocuments.mx/reader031/viewer/2022021716/5ce2653788c993ab258bc0df/html5/thumbnails/9.jpg)
Bathymetry
![Page 10: Hydrodynamic and Thermal Dispersion Modelling of the … · Hydrodynamic and Thermal Dispersion Modelling of the Effluent in a Coastal Channel . Ahmad Sana, sana@squ.edu.om. Sultan](https://reader031.vdocuments.mx/reader031/viewer/2022021716/5ce2653788c993ab258bc0df/html5/thumbnails/10.jpg)
Tidal elevation at sea boundary
![Page 11: Hydrodynamic and Thermal Dispersion Modelling of the … · Hydrodynamic and Thermal Dispersion Modelling of the Effluent in a Coastal Channel . Ahmad Sana, sana@squ.edu.om. Sultan](https://reader031.vdocuments.mx/reader031/viewer/2022021716/5ce2653788c993ab258bc0df/html5/thumbnails/11.jpg)
Tidal elevation close to outlet
![Page 12: Hydrodynamic and Thermal Dispersion Modelling of the … · Hydrodynamic and Thermal Dispersion Modelling of the Effluent in a Coastal Channel . Ahmad Sana, sana@squ.edu.om. Sultan](https://reader031.vdocuments.mx/reader031/viewer/2022021716/5ce2653788c993ab258bc0df/html5/thumbnails/12.jpg)
Thermal dispersion
![Page 13: Hydrodynamic and Thermal Dispersion Modelling of the … · Hydrodynamic and Thermal Dispersion Modelling of the Effluent in a Coastal Channel . Ahmad Sana, sana@squ.edu.om. Sultan](https://reader031.vdocuments.mx/reader031/viewer/2022021716/5ce2653788c993ab258bc0df/html5/thumbnails/13.jpg)
Bottom shear stress
![Page 14: Hydrodynamic and Thermal Dispersion Modelling of the … · Hydrodynamic and Thermal Dispersion Modelling of the Effluent in a Coastal Channel . Ahmad Sana, sana@squ.edu.om. Sultan](https://reader031.vdocuments.mx/reader031/viewer/2022021716/5ce2653788c993ab258bc0df/html5/thumbnails/14.jpg)
Possibility of sediment movement According to Shields Criterion for uniform bed material sizes, the sediment movement will be initiated if
In the present case, τb<0.03 N/m2, ρs-ρ=1650kg/m3, g = 9.81m/s2, Dmin = 0.075mm
No sediment movement will occur
![Page 15: Hydrodynamic and Thermal Dispersion Modelling of the … · Hydrodynamic and Thermal Dispersion Modelling of the Effluent in a Coastal Channel . Ahmad Sana, sana@squ.edu.om. Sultan](https://reader031.vdocuments.mx/reader031/viewer/2022021716/5ce2653788c993ab258bc0df/html5/thumbnails/15.jpg)
Conclusions • Detailed information regarding water level, temperature,
depth averaged velocity and bed shear stress is available within the model domain.
• During the period of prediction, the effect of effluent discharge on the seawater temperature remains confined within the lagoon area.
• Seawater quality by virtue of temperature meets the MECA requirements since the zone of influence of the effluent is confined within the lagoon area where the discharge point is located.
• Extremely low values of bed shear stress in the model domain suggest that the possibility of erosion and therefore accretion of eroded material is remote.
![Page 16: Hydrodynamic and Thermal Dispersion Modelling of the … · Hydrodynamic and Thermal Dispersion Modelling of the Effluent in a Coastal Channel . Ahmad Sana, sana@squ.edu.om. Sultan](https://reader031.vdocuments.mx/reader031/viewer/2022021716/5ce2653788c993ab258bc0df/html5/thumbnails/16.jpg)
Thank You