scholarly journals Past and current sediment dispersion pattern estimates through numerical modeling of wave climate: an example of the Holocene delta of the Doce River, Espírito Santo, Brazil

2007 ◽  
Vol 79 (2) ◽  
pp. 333-341 ◽  
Author(s):  
Abílio C.S.P. Bittencourt ◽  
José M.L. Dominguez ◽  
Louis Martin ◽  
Iracema R. Silva ◽  
Karla O.P. de-Medeiros
Keyword(s):  
Numerical Modeling ◽  
Boundary Conditions ◽  
Late Holocene ◽  
Climate Model ◽  
Coastal Region ◽  
Wave Climate ◽  
Aerial Photographs ◽  
Dispersion Pattern ◽  
Dispersion Patterns ◽  
Doce River

This paper presents a numerical modeling estimation of the sediment dispersion patterns caused by waves inciding through four distinct coastline contours of the delta plain of the Doce River during the Late Holocene. For this, a wave climate model based on the construction of wave refraction diagrams, as a function of current boundary conditions, was defined and was assumed to be valid for the four coastlines. The numerical modeling was carried out on basis of the refraction diagrams, taking into account the angle of approximation and the wave height along the coastline. The results are shown to be comparable with existing data regarding the directions of net longshore drift of sediments estimated from the integration of sediment cores, interpretation of aerial photographs and C14 datings. This fact apparently suggests that, on average, current boundary conditions appear to have remained with the same general characteristics since 5600 cal yr BP to the present. The used approach may prove useful to evaluate the sediment dispersion patterns during the Late Holocene in the Brazilian east-northeast coastal region.

scholarly journals A diachronic view of the net longshore sediment drift during the Late Holocene at the Jequitinhonha River delta, Brazil, using numerical modeling

2011 ◽  
Vol 83 (4) ◽  
pp. 1207-1220 ◽  
Author(s):  
Abilio C.S.P. Bittencourt ◽  
José M.L. Dominguez ◽  
Clemente A.S. Tanajura ◽  
Iracema R. Silva ◽  
Louis Martin
Keyword(s):  
Numerical Modeling ◽  
Late Holocene ◽  
Sediment Cores ◽  
Coastal Region ◽  
River Delta ◽  
Angle Of Incidence ◽  
Delta Plain ◽  
Sediment Drift ◽  
Longshore Drift ◽  
Average Current

Using numerical modeling, this work estimates sediment dispersion patterns caused by the incidence of waves in five distinct coastline contours of the Jequitinhonha River delta plain during the Late Holocene. For this study, a wave cliate odel based on the construction of ave refraction diagras relative to the current boundary conditions as defined and assumed to be valid for the five coastlines. Numerical modeling from the refraction diagrams was carried out considering the angle of incidence and wave height along the coastline. This work has allowed us to reproduce past and current patterns of net longshore sediment drift defined by a conceptual model developed from the integration of sediment cores, aerial photograph interpretation, C14 datings and geomorphic indicators of longshore drift. These results show that, on average, current wave conditions in the east-northeastern Brazilian region seem to have remained characteristically the same from approximately 5100 years BP until the present time. This type of information can be important when attempting to simulate possible future situations in terms of the long-term general behavior of the east-northeastern Brazilian coastal region.

scholarly journals A significant longshore transport divergence zone at the Northeastern Brazilian coast: implications on coastal Quaternary evolution

2002 ◽  
Vol 74 (3) ◽  
pp. 505-518 ◽  
Author(s):  
ABÍLIO C.S.P. BITTENCOURT ◽  
LOUIS MARTIN ◽  
JOSÉ M.L. DOMINGUEZ ◽  
IRACEMA R. SILVA ◽  
DAIANA L. SOUSA
Keyword(s):  
Climate Model ◽  
Coastal Region ◽  
Wave Climate ◽  
Brazilian Coast ◽  
Wave Fronts ◽  
Longshore Transport ◽  
Longshore Drift ◽  
Significant Divergence ◽  
The Mean

By using the mean directions of the wave-fronts approaching the Brazilian northeastern coastal stretch comprised between the localities of Real river (Sergipe State) and Galinhos (Rio Grande do Norte State) - coincident with those of the main winds occurring in the area - and their periods, we have defined a wave climate model based on the construction of refraction diagrams. The resulting model of sediment transport, as obtained by numerical modelling from the refraction diagrams, taking into consideration the angle of approach and waves heights along the 10-m isobath, was capable of reproducing the patterns of sediment dispersion provided by geomorphic indicators of the longshore drift. All this coastal region, approximately 900 km in length, is characterized by a significant divergence zone in the direction of net longshore drift of sediments, the potential intensity of which increases considerably in value, in almost its entire length, continuously toward downdrift, which might explain the greater or lesser long term susceptibility to erosion, during the Quaternary, along the coastal stretch studied.

Upon Impact Numerical Modeling of Foam Materials

2017 ◽  
Vol 54 (2) ◽  
pp. 195-202
Author(s):  
Vasile Nastasescu ◽  
Silvia Marzavan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Modeling ◽  
Numerical Analysis ◽  
Numerical Methods ◽  
Boundary Conditions ◽  
General Character ◽  
Foam Material ◽  
Various Boundary Conditions ◽  
Specific Behaviour

The paper presents some theoretical and practical issues, particularly useful to users of numerical methods, especially finite element method for the behaviour modelling of the foam materials. Given the characteristics of specific behaviour of the foam materials, the requirement which has to be taken into consideration is the compression, inclusive impact with bodies more rigid then a foam material, when this is used alone or in combination with other materials in the form of composite laminated with various boundary conditions. The results and conclusions presented in this paper are the results of our investigations in the field and relates to the use of LS-Dyna program, but many observations, findings and conclusions, have a general character, valid for use of any numerical analysis by FEM programs.

scholarly journals Numerical Modeling of the Motion of the Flat Textile Structures

2011 ◽  
Vol 2011 ◽  
pp. 1-8
Author(s):  
Piotr Szablewski
Keyword(s):  
Numerical Modeling ◽  
Boundary Conditions ◽  
Discrete Model ◽  
Gravity Force ◽  
Dynamic Conditions ◽  
Textile Structure ◽  
Sewing Thread ◽  
Lagrange’S Equations ◽  
Lagrange's Equations ◽  
Time Boundary

In many problems from the field of textile engineering (e.g., fabric folding, motion of the sewing thread) it is necessary to investigate the motion of the objects in dynamic conditions, taking into consideration the influence of the forces of inertia and changing in the time boundary conditions. This paper deals with the model analysis of the motion of the flat textile structure using Lagrange's equations in two variants: without constraints and with constraints. The motion of the objects is under the influence of the gravity force. Lagrange's equations have been used for discrete model of the structure.

Numerical modeling of shoreline undulations part 1: Constant wave climate

2013 ◽  
Vol 75 ◽  
pp. 64-76 ◽  
Author(s):  
Kasper Kaergaard ◽  
Jørgen Fredsoe
Keyword(s):  
Numerical Modeling ◽  
Wave Climate

Does the Contrast Dispersion Pattern During Fluoroscopically Guided Cervical Transforaminal Epidural Steroid Injection Predict Short-Term Pain and Functional Outcomes? An Exploratory Analysis of Prospective Cohort Data

Pain Medicine ◽  
2020 ◽  
Vol 21 (12) ◽  
pp. 3350-3359
Author(s):  
Aaron Conger ◽  
Beau P Sperry ◽  
Cole W Cheney ◽  
Keith Kuo ◽  
Russel Petersen ◽  
...  
Keyword(s):  
Neck Pain ◽  
Epidural Space ◽  
Functional Outcomes ◽  
Steroid Injection ◽  
Epidural Steroid Injection ◽  
Dispersion Pattern ◽  
Arm Pain ◽  
Dispersion Patterns ◽  
Transforaminal Epidural Steroid Injection ◽  
Epidural Steroid

Abstract Summary of Background Data No study has evaluated the relationship between contrast dispersion patterns and outcomes after fluoroscopically guided cervical transforaminal epidural steroid injection (CTFESI). Objectives Determine whether contrast dispersion patterns predict pain and functional outcomes after CTFESI. Methods Secondary analysis of data collected during two prospective studies of CTFESI for the treatment of refractory radicular pain. Contrast dispersion patterns visualized by true anteroposterior (AP) projections during CTFESIs were categorized by flow: 1) completely external to the lateral border of the neuroforamen (zone 1); 2) within the neuroforamen but without entry into the lateral epidural space (zone 2); and 3) with extension into the lateral epidural space (zone 3). At baseline and at 1 month post-CTFESI, neck pain, arm pain, and “dominant index pain” (the greater of arm or neck pain) were evaluated using a numeric rating scale (NRS); physical function was assessed using the Five-Item Version of the Neck Disability Index (NDI-5). Results One-month post-CTFESI, neck pain, arm pain, and “dominant index pain” reductions of ≥50% were observed in 39.4% (95% confidence interval [CI], 28.2–51.8), 55.6% (95% CI, 43.0–67.5), and 44.1% (95% CI, 32.7–56.2) of participants, respectively. Regarding “dominant index pain,” 72.7% (95% CI, 40.8–91.2), 39.4% (95% CI, 24.2–57.0), and 37.5% (95% CI, 20.5–58.2) of participants reported ≥50% pain reduction when zone 1, zone 2, and zone 3 contrast flow patterns were observed. Contrast dispersion zone was not significantly associated with subgroup differences in neck pain, arm pain, or NDI-5 scores (P>0.05). Conclusion Improvements in pain and function 1 month after treatment with CTFESI did not differ significantly based on the contrast dispersion pattern. Future study is needed to confirm or refute these findings in other procedural settings, in broader patient populations, and with longer-term outcome assessment.

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