scholarly journals Transformation of slope runoff base on inflow condition and slope

2020 ◽  
Vol 508 ◽  
pp. 012115
Author(s):  
Li Li ◽  
Binbin Li ◽  
Jing Lin ◽  
Jinhu Zhang ◽  
Lixin Zhang ◽  
...  
Keyword(s):  
Inflow Condition ◽  
Slope Runoff

Numerical Simulation of Flows in a Pipe with an Aneurismal Sac (Effects of Aneurismal Models and Stents)

2008 ◽  
Vol 33-37 ◽  
pp. 1025-1030
Author(s):  
Gulbahar Wahap ◽  
Tatsuya Kobori ◽  
Yoko Takakura ◽  
Norio Arai ◽  
Yoshifumi Konishi ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Reynolds Number ◽  
Human Blood ◽  
Steady States ◽  
Computational Results ◽  
Two Dimensional ◽  
Blood Flows ◽  
Inflow Condition ◽  
Inflow Conditions ◽  
Two Dimensional Flows

Recently, the intravascular therapy using microcoils and stents to treat aneurysms has attracted researcher’s interest. In this study, in order to evaluate the effects of the stents, a numerical simulation of two-dimensional flows has been carried out for a pipe with a model of an aneurismal sac. Using aneurismal models with different inclined angles to the pipe, inflow conditions with steady states or pulsations have been applied in the range of Reynolds number in human blood flows. First, the computational results are compared with experiments under the steady inflow condition, which has shown the reliability of the numerical simulation. Furthermore, the mechanism of flows with an aneurismal model is discussed in the case with or without a stent, and consequently the effect of the stent is clarified.

Experimental Study on Fluid Mixing for Evaluation of Thermal Striping in T-Pipe Junction

2002 ◽  
Author(s):  
Minoru Igarashi ◽  
Masaaki Tanaka ◽  
Shigeyo Kawashima ◽  
Hideki Kamide
Keyword(s):  
Temperature Fluctuation ◽  
Velocity Ratio ◽  
Impinging Jet ◽  
Fluid Mixing ◽  
Cold Spot ◽  
Wall Jet ◽  
Fluid Temperature ◽  
Thermochromic Liquid Crystal ◽  
Inflow Condition ◽  
Thermal Striping

A water experiment is performed to investigate thermal striping phenomena in a T-pipe junction which is a typical geometry of fluid mixing. The flow velocity ratio and temperature difference were experimental parameters. The jet form was classified into four patterns; (1) impinging jet, (2) deflecting jet, (3) re-attachment jet and (4) wall jet according to the inflow condition. The parameter experiments showed that the jet form could be predicted by a momentum ratio between the two pipes. The thermochromic liquid crystal sheet showed that a cold spot was formed at the wall surface in the main pipe in the cases of the impinging jet and the wall jet. From the temperature measurement in the fluid, temperature fluctuation intensity was high along the edge of the jet exiting from branch piping. A database of temperature fluctuation and frequency characteristics was established for an evaluation rule of thermal striping in a T-pipe junction.

Regulation and Critical Threshold of Grass Cover on Slope Runoff in LoessHilly Gully Region under Artificial

2021 ◽  
Author(s):  
Qiufen Zhang ◽  
Xizhi Lv ◽  
Rongxin Chen ◽  
Yongxin Ni ◽  
Li Ma
Keyword(s):  
Soil Erosion ◽  
Rainfall Intensity ◽  
Climatic Conditions ◽  
Vegetation Coverage ◽  
Critical Threshold ◽  
Runoff Generation ◽  
Grassland Vegetation ◽  
Slope Flow ◽  
The Impact ◽  
Slope Runoff

<p>The slope runoff caused by rainstorm is the main cause of serious soil and water loss in the loess hilly area, the grassland vegetation has a good inhibitory effect on the slope runoff, it is of great significance to reveal the role of grassland vegetation in the process of runoff generation and control mechanism for controlling soil erosion in this area. In this study, typical grassland slopes in hilly and gully regions of the loess plateau were taken as research objects. Through artificial rainfall in the field, the response rules of slope rainfall-runoff process to different grass coverage were explored. The results show that: (1) The time for the slope flow to stabilize is prolonged with the increase of vegetation coverage, and shortened with the increase of rainfall intensity; (2) At 60 mm·h <sup>−1</sup> rainfall intensity, the threshold of grassland vegetation coverage is 75.38%; at 90 mm·h<sup> −1</sup> rainfall intensity, the threshold of grassland vegetation coverage is 90.54%; at 120 mm·h <sup>−1</sup> rainfall intensity, the impact of grassland vegetation coverage on runoff is not significant; (3) the Reynolds number and Froude number of slope flow are 40.07‒695.22 and 0.33‒1.56 respectively, the drag coefficient is 1.42‒43.53. Under conditions of heavy rainfall, the ability of grassland to regulate slope runoff is limited. If only turf protection is considered, about 90% of grassland coverage can effectively cope with soil erosion caused by climatic conditions in loess hilly and gully regions. Therefore, in loess hilly areas where heavy rains frequently occur, grassland's protective effect on soil erosion is obviously insufficient, and investment in vegetation measures for trees and shrubs should be strengthened.</p>

Perturbing the inflow condition in shallow mixing layer experiments

Shallow Flows ◽  
2004 ◽  
pp. 95-102
Author(s):  
Wim Uijttewaal ◽  
Michel de Nijs ◽  
Bram C van Prooijen
Keyword(s):  
Mixing Layer ◽  
Inflow Condition

scholarly journals Experimental study on determining Manning roughness coefficient during slope runoff process

2020 ◽  
Vol 39 (4) ◽  
pp. 651-659
Author(s):  
Yashan CHENG ◽  
Zhonggen WANG ◽  
Jun LI ◽  
Zhen HUANG ◽  
Xiangyu YE ◽  
...  
Keyword(s):  
Experimental Study ◽  
Roughness Coefficient ◽  
Manning Roughness ◽  
Slope Runoff ◽  
Manning Roughness Coefficient

Assessing the performance of conservation measures for controlling slope runoff and erosion using field scouring experiments

2022 ◽  
Vol 259 ◽  
pp. 107212
Author(s):  
Liquan Sun ◽  
Biao Zhang ◽  
Ziming Yin ◽  
Huili Guo ◽  
Kadambot H.M. Siddique ◽  
...  
Keyword(s):  
Conservation Measures ◽  
Slope Runoff

Refined Performance Results on a Slowed Mach-Scaled Rotor at High Advance Ratios

2020 ◽  
Vol 65 (1) ◽  
pp. 1-13
Author(s):  
Xing Wang ◽  
Lauren Trollinger ◽  
Inderjit Chopra
Keyword(s):  
Wind Tunnel ◽  
High Speed ◽  
Reverse Flow ◽  
Flow Region ◽  
Comprehensive Analysis ◽  
Compressibility Effect ◽  
Inflow Condition ◽  
Advance Ratio ◽  
Slowed Rotor ◽  
Performance Results

Owing to its ability to alleviate the compressibility effect on the advancing side, the slowed rotor operating at high advance ratios is a key feature in high-speed compound rotorcraft. A series of wind tunnel tests were conducted in the Glenn L. Martin Wind Tunnel with a four-bladed Mach-scaled articulated rotor. The objective of the tests was to gain a basic understanding of unique features of high-advance-ratio aerodynamic phenomena, such as thrust reversal and dynamic stall in the reverse flow region. In this study, high-advance-ratio tests were carried out with highly similar, noninstrumented blades and on-hub control angle measurements, to minimize possible error due to blade structural dissimilarity and pitch angle discrepancy. The tests were conducted at 900 and 1200 RPM, advance ratios of 0.3–0.9, and a shaft tilt study was conducted at±4°. Pitch and flap motion at the blade roots, rotor performance, and vibratory hub loads were investigated during the test. The test data were then compared with those of previous tests and with predictions from comprehensive analysis. The airload results were investigated using comprehensive analysis to gain insights into the influences of advance ratio and shaft tilt angle on rotor performance and hub vibratory loads. Results indicate that the thrust benefit from backward shaft tilt is dependent on the change in the inflow condition and the induced angle of attack increment, and the reverse flow region at high advance ratios is the major contributor to changes in shaft torque and horizontal force.

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