Effect of Molecular Parameters on the Flow Rate Dependence of Drag Reduction and Similar Phenomena

1980 ◽  
pp. 373-385 ◽  
Keyword(s):  
Drag Reduction ◽  
Flow Rate ◽  
Rate Dependence ◽  
Molecular Parameters

Luminal flow rate regulates proximal tubule H-HCO3 transporters

1992 ◽  
Vol 262 (1) ◽  
pp. F47-F54 ◽  
Author(s):  
P. A. Preisig
Keyword(s):  
Proximal Tubule ◽  
Flow Rate ◽  
Initial Rate ◽  
Apical Membrane ◽  
Basolateral Membrane ◽  
Rate Dependence ◽  
Unstirred Layer ◽  
Disulfonic Acid ◽  
Luminal Flow

In vivo microperfusion was used to examine the mechanism of luminal flow rate dependence of proximal tubule acidification. Luminal flow rate was acutely changed between 5 and 40 nl/min, while luminal and peritubular capillary composition were held constant. With inhibition of basolateral membrane base transport by peritubular 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid (DIDS), cell pH (pHi) provides a sensitive index of apical membrane H secretory activity. At a luminal perfusate [HCO3] of 25 mM, progressive increases in luminal flow rate (5----15----25----40 nl/min) caused progressive increases in pHi. This effect was of a smaller magnitude with a luminal perfusate [HCO3] of 60 mM and was further decreased at a luminal perfusate [HCO3] of 100 mM. This pattern of diminished flow rate dependence at higher luminal [HCO3] is consistent with the presence of a luminal unstirred layer, whose composition can be modified by luminal flow rate. The activity of the apical membrane Na-H antiporter, assayed as the initial rate of pHi recovery from an acid load in the presence of peritubular DIDS, was faster at 40 compared with 5 nl/min. Basolateral membrane Na-3HCO3 symporter activity, assayed as the initial rate of pHi recovery from an alkali load in the absence of luminal and peritubular chloride, was faster at 40 compared with 5 nl/min. This effect was eliminated by luminal amiloride, suggesting an indirect effect of flow mediated by changes in pHi secondary to flow rate-dependent changes in apical membrane Na-H antiporter activity. In summary, increases in luminal flow rate directly increase apical membrane H secretion, possibly by modification of a luminal unstirred layer.(ABSTRACT TRUNCATED AT 250 WORDS)

Flow Rate Dependence of Soil Hydraulic Characteristics

2001 ◽  
Vol 65 (1) ◽  
pp. 35-48 ◽  
Author(s):  
D. Wildenschild ◽  
J.W. Hopmans ◽  
J. Simunek
Keyword(s):  
Flow Rate ◽  
Rate Dependence ◽  
Hydraulic Characteristics ◽  
Soil Hydraulic

Mechanical Impact Effects of Fluid Hammer Effects on Drag Reduction of Coiled Tubing

2021 ◽  
pp. 1-10
Author(s):  
Yongsheng Liu ◽  
Xing Qin ◽  
Yuchen Sun ◽  
Zijun Dou ◽  
Jiansong Zhang ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Drag Reduction ◽  
Flow Rate ◽  
Fluid Velocity ◽  
Fluid Pressure ◽  
Great Influence ◽  
Radial Force ◽  
Fluid Flow Rate ◽  
Normal Contact ◽  
Coiled Tubing

Abstract Aiming at the oscillation drag reduction tool that improves the extension limit of coiled tubing downhole operations, the fluid hammer equation of the oscillation drag reducer is established based on the fluid hammer effect. The fluid hammer equation is solved by the asymptotic method, and the distribution of fluid pressure and flow velocity in coiled tubing with oscillation drag reducers is obtained. At the same time, the axial force and radial force of the coiled tubing caused by the fluid hammer oscillator are calculated according to the momentum theorem. The radial force will change the normal contact force of the coiled tubing which has a great influence on frictional drag. The results show that the fluid flow rate and pressure decrease stepwise from the oscillator position to the wellhead position, and the fluid flow rate and pressure will change abruptly during each valve opening and closing time. When the fluid passes through the oscillator, the unit mass fluid will generate an instantaneous axial tension due to the change in the fluid velocity, thereby converting the static friction into dynamic friction, which is conducive to the extend limit of coiled tubing.

scholarly journals Intermittent Chaos in the CSTR Bray–Liebhafsky Oscillator-Specific Flow Rate Dependence

2020 ◽  
Vol 8 ◽  
Author(s):  
Itana Nuša Bubanja ◽  
Ana Ivanović-Šašić ◽  
Željko Čupić ◽  
Slobodan Anić ◽  
Ljiljana Kolar-Anić
Keyword(s):  
Flow Rate ◽  
Rate Dependence ◽  
Specific Flow Rate ◽  
Specific Flow ◽  
Intermittent Chaos

Influence of fluid flow on the stability and wetting transition of submerged superhydrophobic surfaces

Soft Matter ◽  
2016 ◽  
Vol 12 (18) ◽  
pp. 4241-4246 ◽  
Author(s):  
Yaolei Xiang ◽  
Yahui Xue ◽  
Pengyu Lv ◽  
Dandan Li ◽  
Huiling Duan
Keyword(s):  
Fluid Flow ◽  
Drag Reduction ◽  
Flow Rate ◽  
Convective Diffusion ◽  
Superhydrophobic Surfaces ◽  
Diffusion Regime ◽  
Wetting Transition ◽  
The Stability

The stability of submerged superhydrophobic surfaces for drag reduction significantly depends on the flow rate by a convective diffusion regime.

Surface and kinetic effects in gas chromatographic studies of polystyrene

1976 ◽  
Vol 54 (22) ◽  
pp. 3496-3507 ◽  
Author(s):  
Gregory J. Courval ◽  
Derek G. Gray
Keyword(s):  
Sample Size ◽  
Flow Rate ◽  
Retention Volume ◽  
Rate Dependence ◽  
Retention Data ◽  
Scanning Electron Micrographs ◽  
Linear Absorption ◽  
Solvent Interactions ◽  
Non Linear ◽  
Polymer Solvent

Considerable variation in the measurement of polymer–solvent interactions using gc retention data may occur due to kinetic factors, surface excess concentrations of probe vapour, and non-linear partition isotherms. The kinetic factors, which appear as a flow rate dependence of the retention volume, are analysed in terms of a previously reported theoretical model for retention on polymeric stationary phases passing through the glass transition. The predicted linear extrapolations to zero flow rate are obtained for the retention of n-tetradecane on polystyrene. The variation of this flow rate dependence with temperature and with the thickness of the stationary phase are also in qualitative agreement with the theory. A simplified model for the effect of loading on the retention diagram is presented. Non-linear absorption and bulk sorption isotherms result in a dependence of retention volume on sample size, necessitating an extrapolation of the measured retention volumes to zero peak height. The temperature variation of the flow rate dependence, the effect of loading, and the effect of sample size on retention volume are all further complicated by uneven distribution of polymer on support. From scanning electron micrographs of the beads it is evident that 'beading up' of the polystyrene on the glass surface may occur at low loadings, resulting in a non-uniform coating with large areas of the beads uncoated. It is concluded that in order to obtain reliable data on polymer–solvent interactions using gas chromatography, all of the above-mentioned factors must be considered.

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