In this paper, shear, effective stress and pore pressure distributions of two-layer porous soils subjected to harmonic waves are presented. The instability of the porous soil because of wave loading is investigated in terms of instantaneous liquefaction. The governing equations are written in their fully dynamic form, and possible simplifications are introduced. Finite-element models are developed for each formulation, and numerical results are verified with their corresponding analytical solutions, which are also developed here. Then, the problem of a two-layer soil under waves both in an open domain and in front of a vertical wall is studied in terms of dynamic response variations and regions of instantaneous liquefaction. Both linear and nonlinear waves are considered. Finally, a number of parametric studies to investigate the effect of a surface clay layer, inertial terms in the equations, various soil and wave parameters, and wave nonlinearity on the dynamic behavior and instability are carri...

Pore Pressure, Stress Distributions, and Instantaneous Liquefaction of Two-Layer Soil under Waves

We report experiments on windblown sand that highlight a transition from saltation to collisional regime above a critical dimensionless mass flux or Shields number. The transition is first seen through the mass flow rate Q, which deviates from a linear trend with the Shields number and seems to follow a quadratic law. Other physical evidences confirm the change of the transport properties. In particular, the particle velocity and the height of the transport layer increases with increasing Shields number in the collisional regime while the latter are invariant with the wind strength in the saltation regime. Discrete numerical simulations support the experimental findings and ascertain that mid-air collisions are responsible for the change of transport regime.

/pdf/transition-from-saltation-to-collisional-regime-in-windblown-fygoxhy137.pdf

Transition from Saltation to Collisional Regime in Windblown Sand

Since the 2010 Deepwater Horizon (DWH) oil spill, the Gulf of Mexico Research Initiative (GOMRI) has studied the oil spill from the perspectives of ocean environment, ecosystems, socioeconomics and human health. As GOMRI sunsets in its tenth year after the DWH oil spill, synthesis efforts recently took place to assess the accomplishments of the program. In this paper, we report on DWH modeling as part of GOMRI's Synthesis and Legacy effort. We compile a list of 330 published applications by GOMRI, the Natural Resource Damage Assessment (NRDA), and others studying the DWH oil spill and look at a wide range of subjects, tools, achievements, and integration with field research. We offer highlights and synthesis based on discussions and public webinars held in 2019 and 2020. We synthesize the significant achievements and advancements that have been made in integrating the various disciplines and domains from a modeling perspective. There was a large diversity of tools used, including at least 74 unique modeling systems. Most studies employed circulation models. These hydrodynamic models were often coupled to wave, river, and atmosphere models, as well as representations of high pressure physics and oil chemistry. Several research groups used Lagrangian transport models and statistical inference to track subsurface oil. Some coupled biophysical models were also employed to study oil fate and weathering, larval transport, biological effects, and population dynamics. In a few cases, such biophysical models were linked to marine populations and to humans through socioeconomics effects and ecosystem services. We consider models made for response planning and remediation, damage assessment, and restoration planning. There are relatively few socioeconomic or human health models, although those few examples make good use of biophysical modeling products. Our conclusions offer some insights on how the development of new tools has better prepared us for studying environmental management challenges in the Gulf of Mexico.

Ten years of modeling the Deepwater Horizon oil spill

Surface Gravity Waves and Their Role in Ocean-Atmosphere Coupling in the Gulf of Mexico

Shoreline evolution due to construction of rubble mound jetties at Munambam inlet in Ernakulam–Trichur district of the state of Kerala in the Indian peninsula

Wave dynamics near Barataria Bay tidal inlets during spring–summer time

Subtidal Water Level and Current Variability in a Bar‐built Estuary during Cold Front Season: Barataria Bay, Gulf of Mexico

The present paper tackles morphological modeling of a rare case of a re-migrating inlet to be used as the basis of a fishery port site selection study. The Tang inlet, located on the south-eastern shores of Iran, has so far been experiencing a cyclic migration with a return period of approximately a decade. In order to grasp the essence of the morphological behavior of the inlet, a two-fold site monitoring campaign was performed, consisting of a shoreline evolution study using aerial & satellite imagery for the outside of the bay as well as a sedimentation pattern comparison based on past hydrographical survey results for the inside of the bay utilizing ArcGIS software. Subsequently, numerical modeling of the inlet comprising of nearshore wave transformation, tidal regime of the bay, one-line coastline evolution and two-dimensional sediment transport within the bay was carried out utilizing MIKE 21 package. Ebb channel switching from a westerly to an easterly orientation is deemed to occur due to self-suffocation as a result of the presence of an existing offshore rock formation, as well as the salient making potential of the rock system. On the other hand, the closure of the east-facing channel is mainly attributed to diffraction currents due to Monsoon southerly waves helped by sedimentation load from inside the bay system due to floods & ebb currents.

/pdf/a-case-study-of-hydrodynamic-and-morphological-modeling-of-a-lem1uxhdtu.pdf

A case study of hydrodynamic and morphological modeling of a re-migrating inlet

A series of laboratory wave-flume experiments was conducted to investigate the dissipation of monochromatic regular waves on a horizontal muddy bed of commercial kaolinite. The rheological parameters of kaolinite samples with different water content ratios were obtained from controlled shear rate tests using the rheometer. The flow curves of shear stress versus shear rate were found to be essentially Bingham viscoplastic medium for steady unidirectional mud flows of the rheological tests. Assuming Bingham behavior for kaolinite, a wave-mud interaction model was employed to obtain the values of the wave attenuation coefficients. Comparisons between the measured and simulated results show a good agreement.

/pdf/wave-flume-experiments-of-dissipating-waves-on-soft-mud-34bk72lxir.pdf

Soroush Sorourian

Papers

Wave dynamics near Barataria Bay tidal inlets during spring–summer time

Subtidal Water Level and Current Variability in a Bar‐built Estuary during Cold Front Season: Barataria Bay, Gulf of Mexico

A case study of hydrodynamic and morphological modeling of a re-migrating inlet

Wave-flume experiments of dissipating waves on soft mud

A modeling study of water and sediment flux partitioning through the major passes of Mississippi Birdfoot Delta and their plume structures