scholarly journals Influence of Topographic Resolution and Accuracy on Hydraulic Channel Flow Simulations: Case Study of the Versilia River (Italy)

2019 ◽  
Vol 11 (13) ◽  
pp. 1630 ◽  
Author(s):  
Luppichini ◽  
Favalli ◽  
Isola ◽  
Nannipieri ◽  
Giannecchini ◽  
...  
Keyword(s):  
Channel Flow ◽  
Flow Rate ◽  
Cross Sections ◽  
Low Cost ◽  
Maximum Flow ◽  
Maximum Flow Rate ◽  
Differential Gps ◽  
Basic Model ◽  
Hydraulic Channel ◽  
Elevation Model

The Versilia plain, a well-known and populated tourist area in northwestern Tuscany, is historically subject to floods. The last hydrogeological disaster of 1996 resulted in 13 deaths and in loss worth hundreds of millions of euros. A valid management of the hydraulic and flooding risks of this territory is therefore mandatory. A 7.5 km-long stretch of the Versilia River was simulated in one-dimension using river cross-sections with the FLO-2D Basic model. Simulations of the channel flow and of its maximum flow rate under different input conditions highlight the key role of topography: uncertainties in the topography introduce much larger errors than the uncertainties in roughness. The best digital elevation model (DEM) available for the area, a 1-m light detection and ranging (LiDAR) DEM dating back to 2008–2010, does not reveal all the hydraulic structures (e.g., the 40 cm thick embankment walls), lowering the maximum flow rate to only 150 m3/s, much lower than the expected value of 400 m3/s. In order to improve the already existing input topography, three different possibilities were considered: (1) to add the embankment walls to the LiDAR data with a targeted Differential GPS (DGPS) survey, (2) to acquire the cross section profiles necessary for simulation with a targeted DGPS survey, and (3) to achieve a very high resolution topography using structure from motion techniques (SfM) from images acquired using an unmanned aerial vehicle (UAV). The simulations based on all these options deliver maximum flow rates in agreement with estimated values. Resampling of the 10 cm cell size SfM-DSM allowed us to investigate the influence of topographic resolution on hydraulic channel flow, demonstrating that a change in the resolution from 30 to 50 cm alone introduced a 10% loss in the maximum flow rate. UAV-SfM-derived DEMs are low cost, relatively fast, very accurate, and they allow for the monitoring of the channel morphology variations in real time and to keep the hydraulic models updated, thus providing an excellent tool for managing hydraulic and flooding risks.

Studies on Micropump/Minipump Using Rotational Motion of Magnetic Material Balls

2013 ◽  
Author(s):  
Hiroshige Kumamaru ◽  
Fuma Sakata ◽  
Akira Ohue ◽  
Kazuhiro Itoh ◽  
Yuji Shimogonya
Keyword(s):  
Magnetic Material ◽  
Flow Rate ◽  
Cross Sections ◽  
Rotational Motion ◽  
Maximum Flow ◽  
Maximum Flow Rate ◽  
Numerical Analyses ◽  
Closed Channel ◽  
Pump Head ◽  
Inner Diameter

Experiments and numerical analyses have been performed on micropumps/minipumps using rotational motion of magnetic material balls. In the pumps, magnetic material balls and nonmagnetic materials balls rotate in a closed channel loop, and a part of the balls acts as a piston and the remaining part of the balls serves as a valve. Experiments have been carried out on two pumps, i.e. a smaller pump and a larger pump with channel cross-sections of ∼1 mm and ∼2 mm inner diameter, respectively. The maximum flow rate achieved and the maximum pump head obtained are ∼500 μl/min and ∼70 Pa, respectively, for the smaller pump, and ∼2000 μl/min and ∼150 Pa, respectively, for the larger pump. Numerical analyses have been performed by dividing the pumping loop into a piston channel and a valve channel. The numerical analyses overestimate the flow rate obtained in the experiments, except for the region of larger pump heads in the larger pump.

Development of a Piezoelectric Micropump with Novel Separable Design

2014 ◽  
Vol 670-671 ◽  
pp. 1426-1429 ◽  
Author(s):  
Wen Fu Luo ◽  
Hsiao Kang Ma
Keyword(s):  
Flow Rate ◽  
Low Cost ◽  
Maximum Flow ◽  
Maximum Flow Rate ◽  
Waste Solution ◽  
Pump Chamber ◽  
Single Use ◽  
Different Depths ◽  
Supply Mode

In this study, partially disposable piezoelectric micropumps with separable design have been developed and discussed. The actuator, a rectangular piezo-plate, can be separated and be used repeatedly while the pump chamber is single-use to prevent infection. Thus, a low cost and waste solution for biomedical uses is achieved. Central bossed design of diaphragm was used to achieve self-return in supply mode. More, pump chambers with different depths and diameters have been made. The maximum flow rate, 15.03 ml/min, is reached under 60V actuated voltage.

Concept of the Partial Throw-Away Design of Piezoelectric Micropump for Medical Uses with Low Cost and Waste

2013 ◽  
Vol 477-478 ◽  
pp. 363-367
Author(s):  
Wen Fu Luo ◽  
Rong Huei Chen ◽  
Hsiao Kang Ma
Keyword(s):  
Flow Rate ◽  
Mechanical Model ◽  
Piezoelectric Plate ◽  
Low Cost ◽  
Maximum Flow ◽  
Maximum Flow Rate ◽  
Waste Solution ◽  
Pump Chamber ◽  
Single Use ◽  
Rectangular Piezoelectric Plate

In this study, piezoelectric micropumps with partial throw-away design have been developed and discussed. The actuator, a rectangular piezoelectric plate, can be separated from the pump body and be used repeatedly while the pump chamber is single-use to prevent infection. Thus, a low cost and waste solution for biomedical uses is achieved. A mechanical model is used to analyze the behavior of pump diaphragm and chamber geometry. Pump chamber with 20mm diameter is used due to its moderate elasticity. Then, 5 pumps with different depth of pump chamber have been made. The maximum flow rate, 5.7g/min, is reached by using a 0.5mm pump chamber with a 200V actuated voltage.

Development of a low-cost flow meter to grade the maximum flow rate

2001 ◽  
Vol 21 (1) ◽  
pp. 48-54 ◽  
Author(s):  
J.J.M. Pel ◽  
R. van Mastrigt
Keyword(s):  
Flow Rate ◽  
Low Cost ◽  
Maximum Flow ◽  
Maximum Flow Rate ◽  
Flow Meter ◽  
Cost Flow

Lichen sclerosis–induced long segment anterior urethral stricture: The early outcome of one-stage repair using dorsolateral onlay buccal mucosa graft

2021 ◽  
pp. 039156032110033
Author(s):  
Atef Fathi ◽  
Omar Mohamed ◽  
Osama Mahmoud ◽  
Gamal A Alsagheer ◽  
Ahmed M Reyad ◽  
...  
Keyword(s):  
Success Rate ◽  
Urethral Stricture ◽  
Flow Rate ◽  
Urine Volume ◽  
Maximum Flow ◽  
Maximum Flow Rate ◽  
P Value ◽  
Onlay Graft ◽  
Voiding Symptoms ◽  
Stricture Recurrence

Background: Substitution urethroplasty using buccal mucosal grafts can be performed by several approaches including ventral onlay graft, dorsal onlay graft, or ventral urethrotomy with dorsal inlay graft. Our study aims to evaluate the surgical outcome of dorsolateral buccal mucosal graft for long segment anterior urethral stricture >6 cm in patients with Lichen sclerosus (LS). Methods: A retrospective study included patients who underwent repair for long segment anterior urethral stricture >6 cm due to LS between January 2013 and April 2019. All patients were followed-up at 3, 6, 9, and 12 months postoperatively and then yearly by clinical symptoms, uroflowmetry, and calculation of post-void residual urine volume. Retrograde urethrogram was requested for patients with voiding symptoms or decreased maximum flow rate. Stricture recurrence that required subsequent urethrotomy or urethroplasty was considered failure. The success rate and surgical complications were collected and analyzed. Results: Thirty patients were identified. The median age (range) was 39 (25–61) years and a median (range) stricture length was 8 (6–14) cm. Most of postoperative complications were of minor degree. The success rate at median follow-up of 15 (12–24) months was 86.5%. The median maximum flow rate increased significantly from 6 (2–11) ml/s preoperatively to 18 (range: 6–23) ml/s at the 6th month ( p value < 0.001). Conclusion: Dorsolateral buccal mucosal grafts urethroplasty for long anterior urethral stricture caused by LS has a high success rate and low risk of complications including stricture recurrence.

scholarly journals Maximum Flow Rate of a Single Component, Two-Phase Mixture

1965 ◽  
Vol 87 (1) ◽  
pp. 134-141 ◽  
Author(s):  
F. J. Moody
Keyword(s):  
Flow Rate ◽  
Static Pressure ◽  
Maximum Flow ◽  
Single Component ◽  
Maximum Flow Rate ◽  
Vapor Flow ◽  
Two Phase ◽  
Slip Ratio ◽  
Phase Mixture ◽  
Local Slip

A theoretical model is developed for predicting the maximum flow rate of a single component, two-phase mixture. It is based upon annular flow, uniform linear velocities of each phase, and equilibrium between liquid and vapor. Flow rate is maximized with respect to local slip ratio and static pressure for known stagnation conditions. Graphs are presented giving maximum steam/water flow rates for: local static pressures between 25 and 3,000 psia, with local qualities from 0.01 to 1.00; local stagnation pressures and enthalpies which cover the range of saturation states.

Effect of Blade Angle of Attack and Hub to Tip Ratio on Mass Flow Rate in an Axial Fan at a Fixed Rotational Speed

2008 ◽  
Author(s):  
Mohammad J. Izadi ◽  
Alireza Falahat
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Rotational Speed ◽  
Angle Of Attack ◽  
Maximum Flow ◽  
Maximum Flow Rate ◽  
Maximum Mass ◽  
Blade Angle ◽  
Axial Fan

In this investigation an attempt is made to find the best hub to tip ratio, the maximum number of blades, and the best angle of attack of an axial fan with flat blades at a fixed rotational speed for a maximum mass flow rate in a steady and turbulent conditions. In this study the blade angles are varied from 30 to 70 degrees, the hub to tip ratio is varied from 0.2 to 0.4 and the number of blades are varied from 2 to 6 at a fixed hub rotational speed. The results show that, the maximum flow rate is achieved at a blade angle of attack of about 45 degrees for when the number of blades is set equal to 4 at most rotational velocities. The numerical results show that as the hub to tip ratio is decreased, the mass flow rate is increased. For a hub to tip ratio of 0.2, and an angle of attack around 45 degrees with 4 blades, a maximum mass flow rate is achieved.

The characters exploration of a piezoelectric pump with fishtail-shaped bluffbody

2021 ◽  
pp. 1045389X2110386
Author(s):  
Yi Hou ◽  
Lipeng He ◽  
Zheng Zhang ◽  
Baojun Yu ◽  
Hong Jiang ◽  
...  
Keyword(s):  
Flow Rate ◽  
Preliminary Investigation ◽  
Maximum Flow ◽  
Theoretical Explanation ◽  
Maximum Flow Rate ◽  
Bluff Bodies ◽  
Conical Flow ◽  
Piezoelectric Pump ◽  
Valveless Piezoelectric Pump ◽  
Shape And Size

This paper focuses on a new structure in the valveless piezoelectric pump, which has a combination structure of the conical flow channel and two fishtail-shaped bluffbodies in the chamber of the pump. The fishtail-shaped bluffbody is inspired by the shape of the swimming fish to diminish the backflow and optimize the performance of the pump. The performance is studied by changing the shape and size of the inlet and outlet, the bluff bodies’ height and the space between two bluff bodies. The results show that the 3 mm × 3 mm square inlet, 3 mm diameter round outlet, 3 mm height of bluffbodies, 6.8 mm pitch of bluffbodies has a best performance in all 10 prototypes, which implements a maximum flow rate of 87.5 ml/min at 170 V 40 Hz with a noise of 42.6 dB. This study makes a preliminary investigation and theoretical explanation for the subsequent optimization of this structure, improved the performance of the valveless piezoelectric pump, broaden the thinking of the design for the bluffbody for better performance of the valveless piezoelectric pump.

Transport of Particle-Laden Fluids Through Fixed-Valve Micropumps

1999 ◽  
Author(s):  
Ling-Sheng Jang ◽  
Christopher J. Morris ◽  
Nigel R. Sharma ◽  
Ron L. Bardell ◽  
Fred K. Forster
Keyword(s):  
Surface Charge ◽  
Surface Area ◽  
Flow Rate ◽  
Pure Water ◽  
Maximum Flow ◽  
Total Surface Area ◽  
Maximum Flow Rate ◽  
Number Density ◽  
Polystyrene Microspheres ◽  
Negative Surface

Abstract Micropumps designed for the flow-rate range of 100–1000μl/min have been developed by a number of research groups. However, little data is available regarding the ability of various designs to directly transport liquids containing particles such as cells, microspheres utilized for bead chemistry, or contaminants. In this study the ability of pumps with no-moving-parts valves (NMPV) to transport particles was investigated. The results showed that a NMPV micropump was able to directly pump suspensions of polystyrene microspheres from 3.1 to 20.3μm in diameter. The pump functioned without clogging at microsphere number densities as high as 9000 particles/μl of suspension, which corresponded to over 90,000 particles per second passing through the pump at a flow rate of 600μl/min. Performance with polystyrene microspheres was the same as pure water up to the point of cavitation. Microspheres manufactured with negative surface charge cavitated less readily that other microspheres studied that were manufactured without surface charge. However, cavitation did not appear to be a function of microsphere size, total surface area or number density. Thus pumping polystyrene microspheres was found to be more affected by surface effects than by size, surface area or number density within the range of parameters considered. In the case of charged microspheres, the maximum flow rate was reduced by 30% compared to pure water whereas for uncharged microspheres the maximum flow rate was reduced by approximately 80%.

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