The boundary layer equations for plane, incompressible, and steady flow are 

$$\matrix{ {u{{\partial u} \over {\partial x}} + v{{\partial u} \over {\partial y}} = - {1 \over \varrho }{{\partial p} \over {\partial x}} + v{{{\partial ^2}u} \over {\partial {y^2}}},} \cr {0 = {{\partial p} \over {\partial y}},} \cr {{{\partial u} \over {\partial x}} + {{\partial v} \over {\partial y}} = 0.} \cr }$$

Boundary Layer Theory

Regional approach to modeling the transport of floating plastic debris in the Adriatic Sea.

Visual ship transect surveys provide crucial information about the density, and spatial distribution of floating anthropogenic litter in a basin. However, such observations provide a 'snapshot' of local conditions at a given time and cannot be used to deduce the provenance of the litter or to predict its fate, crucial information for management and mitigation policies. Particle tracking techniques have seen extensive use in these roles, however, most previous studies have used simplistic initial conditions based on bulk average inputs of debris to the system. Here, observations of floating anthropogenic macro debris in the Adriatic Sea are used to define initial conditions (number of particles, location, and time) in a Lagrangian particle tracking model. Particles are advected backward and forward in time for 60 days (120 days total) using surface velocities from an operational regional ocean model. Sources and sinks for debris observed in the central and southern Adriatic in May 2013 and March 2015 included the Italian coastline from Pescara to Brindisi, the Croatian island of Mljet, and the coastline from Dubrovnik through Montenegro to Albania. Debris observed in the northern Adriatic originated from the Istrian peninsula to the Italian city of Termoli, as well as the Croatian island of Cres and the Kornati archipelago. Particles spent a total of roughly 47 days afloat. Coastal currents, notably the eastern and western Adriatic currents, resulted in large alongshore displacements. Our results indicate that anthropogenic macro debris originates largely from coastal sources near population centers and is advected by the cyclonic surface circulation until it strands on the southwest (Italian) coast, exits the Adriatic, or recirculates in the southern gyre.

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Combining Litter Observations with a Regional Ocean Model to Identify Sources and Sinks of Floating Debris in a Semi-enclosed Basin: The Adriatic Sea

Diversity and regional distribution of harmful algal events along the Atlantic margin of Europe.

Observed and modeled surface Lagrangian transport between coastal regions in the Adriatic Sea with implications for marine protected areas

. Statistics of transit and residence times in the Adriatic Sea surface, a semi-enclosed basin of the Mediterranean, are estimated from drifter data and Lagrangian numerical simulations. The results obtained from the drifters are generally underestimated given their short operating lifetimes (half life of ∼40 days) compared to the transit and residence times. This bias can be removed by considering a large amount of numerical particles whose trajectories are integrated over a long time (750 days) with a statistical advection–dispersion model of the Adriatic surface circulation. Numerical particles indicate that the maximum transit time to exit the basin is about 216–260 days for particles released near the northern tip of the Adriatic, and that a particle entering on the eastern Otranto Channel will typically exit on the other side of the channel after 170–185 days. A duration of 150–168 days is estimated as the residence time in the Adriatic Basin.

/pdf/transit-and-residence-times-in-the-adriatic-sea-surface-as-2opp5nwl8z.pdf

Transit and residence times in the Adriatic Sea surface as derived from drifter data and Lagrangian numerical simulations

In a future scenario of increasing temperatures in North-Atlantic waters, the risk associated with the expansion of the harmful, benthic dinoflagellate Ostreopsis cf. siamensis has to be evaluated and monitored. Microscopy observations and spatio-temporal surveys of environmental DNA (eDNA) were associated with Lagrangian particle dispersal simulations to: (i) establish the current colonization of the species in the Bay of Biscay, (ii) assess the spatial connectivity among sampling zones that explain this distribution, and (iii) identify the sentinel zones to monitor future expansion. Throughout a sampling campaign carried out in August to September 2018, microscope analysis showed that the species develops in the south-east of the bay where optimal temperatures foster blooms. Quantitative PCR analyses revealed its presence across almost the whole bay to the western English Channel. An eDNA time-series collected on plastic samplers showed that the species occurs in the bay from April to September. Due to the water circulation, colonization of the whole bay from the southern blooming zones is explained by inter-site connectivity. Key areas in the middle of the bay permit continuous dispersal connectivity towards the north. These key areas are proposed as sentinel zones to monitor O. cf. siamensis invasions towards the presumably warming water of the North-East Atlantic.

Current distribution and potential expansion of the harmful benthic dinoflagellate Ostreopsis cf. siamensis towards the warming waters of the Bay of Biscay, North-East Atlantic

/pdf/transit-and-residence-times-in-the-surface-adriatic-sea-as-2mi8kfa4bu.pdf

Transit and residence times in the surface Adriatic Sea as derived from drifter data and Lagrangian numerical simulations

Effects of convex wall curvature on turbulent boundary layer flow are studied in this article using a numerical method. Since the non-linear k−e model often used in engineering applications...

The effect of convex wall curvature on the structure of the turbulent boundary layer

The effects of adverse pressure gradient (APG) on turbulent boundary layer flow are studied in this article using numerical methods. The values of pressure gradient are simulated by Clauser's param...

Saeed Hariri

Papers

Transit and residence times in the Adriatic Sea surface as derived from drifter data and Lagrangian numerical simulations

Current distribution and potential expansion of the harmful benthic dinoflagellate Ostreopsis cf. siamensis towards the warming waters of the Bay of Biscay, North-East Atlantic

Transit and residence times in the surface Adriatic Sea as derived from drifter data and Lagrangian numerical simulations

The effect of convex wall curvature on the structure of the turbulent boundary layer

The Effect of Adverse Pressure Gradient on the Structure of Turbulent Boundary Layer