The effect of wall roughness on velocity distribution in a model of the carotid sinus bifurcation – analysis of laser and ultrasound doppler velocity data

1995 ◽  
Vol 3 (3) ◽  
pp. 153-159
Author(s):  
K. Kaluzynski ◽  
D. Liepsch
Keyword(s):  
Velocity Distribution ◽  
Bifurcation Analysis ◽  
Carotid Sinus ◽  
Doppler Velocity ◽  
Wall Roughness ◽  
Velocity Data ◽  
Ultrasound Doppler

Estimating the hydrodynamic and morphodynamic characteristics using Entropy theory at the confluence of Negro and Solimões Rivers

2021 ◽  
Author(s):  
Farhad Bahmanpouri ◽  
Silvia Barbetta ◽  
Carlo Gualtieri ◽  
Marco Ianniruberto ◽  
Naziano Filizola ◽  
...  
Keyword(s):  
Velocity Distribution ◽  
Flow Characteristics ◽  
Low Flow ◽  
Entropy Theory ◽  
Velocity Data ◽  
Flow Conditions ◽  
Mean Velocity ◽  
Discharge Data ◽  
Confluence Zone ◽  
Error Percentage

<p>When two mega rivers merge the mixing of two flows results in a highly complex three-dimensional flow structure in an area known as the confluence hydrodynamic zone. In the confluence zone, substantial changes occur to the hydrodynamic and morphodynamic features which are of significant interest for researchers. The confluence of the Negro and Solimões Rivers, as one of the largest river junctions on Earth, is the study area of the present research. During the EU-funded Project “Clim-Amazon” (2011-2015), velocity data were collected using an ADCP vessel operating under high and low flow conditions in different locations at that confluence (Gualtieri et al., 2019). By applying the Entropy theory developed by Chiu (1988) for natural channels and simplified by Moramarco et al. (2014), the two-dimensional velocity distribution, as well as depth-averaged velocity, were calculated at the different transects along the confluence zone, using only the surface velocities observation. The estimated data yielded 6.6% and 6.9% error percentage for the discharge data related to high and low flow conditions, respectively, and 8.4% and 8.3% error percentage for the velocity data related to high and low flow conditions, respectively. Regardless of the flow condition, these preliminary results also suggest the potential points at the confluence zone for the maximum local scouring. The findings of the current research highlighted the potential of Entropy theory to estimate the flow characteristics at the large river’s confluence, just starting from the measure of surface velocities. This is of considerable interest for monitoring high flows using no-contact technology, when ADCP or other contact equipment cannot be used for the safety of operators and risks for equipment loss.</p><p> </p><p>Keywords: Amazon River, Negro/Solimões Confluence, Entropy Theory, Velocity Distribution, Local Scouring</p><p>References</p><p>Gualtieri, C., Ianniruberto, M., Filizola, N. (2019). On the mixing of rivers with a difference in density: the case of the Negro/Solimões confluence, Brazil. Journal of Hydrology, 578(11), November 2019, 124029,</p><p>Chiu, C. L. (1988). “Entropy and 2-D velocity distribution in open channels”. Journal of Hydrologic Engineering, ASCE, 114(7), 738-756</p><p>Moramarco, T., Saltalippi, C., Singh, V.P. (2004). “Estimation of mean velocity in natural channels based on Chiu’s velocity distribution equation”. Journal of Hydrologic Engineering, ASCE, 9 (1), pp. 42-50</p>

ON WELL VELOCITY DATA AND THEIR APPLICATION TO REFLECTION SHOOTING

Geophysics ◽  
1946 ◽  
Vol 11 (1) ◽  
pp. 66-81 ◽  
Author(s):  
P. E. Narvarte
Keyword(s):  
Velocity Distribution ◽  
Seismic Reflection ◽  
Time Function ◽  
Velocity Data ◽  
Seismic Reflection Data ◽  
Combined Load ◽  
Contour Maps ◽  
Reflection Data ◽  
Time Relation

Current methods of computing seismic reflection data employing the integration of the actual velocity‐depth (or velocity‐time) relation in the velocity column are confronted with difficulties and limitations because they neglect the stratigraphic effect on the velocity distribution. A method is proposed where the measured incremental time‐depth relation, ΔZ/ΔT, to each of a number of stratigraphic markers may be combined into one generalized depth or time function satisfying well velocity data from a number of wells. The proposed method employs the integration of this slope relation and is used in conjunction with regional correction contour maps. Because this relation results from the combined load and stratigraphic effects together with the geological behavior of the section, this method offers distinct advantages both in accuracy and applicability. Advantages and limitations in the application of this method are discussed.

Analysis of ultrasonic Doppler velocity data obtained in models of stenosed carotid bifurcations with irregular lesion surface

1997 ◽  
Vol 5 (3) ◽  
pp. 199-206 ◽  
Author(s):  
K. Kaluzynski ◽  
B. Lesniak ◽  
K. Mikolajczyk ◽  
D. Liepsch
Keyword(s):  
Doppler Velocity ◽  
Velocity Data
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