Measurements of low‐velocity flow noise on pressure and pressure gradient hydrophones

1974 ◽  
Vol 55 (S1) ◽  
pp. S24-S24 ◽  
Author(s):  
R. A. Finger ◽  
L. A. Abbagnaro ◽  
B. B. Bauer
Keyword(s):  
Pressure Gradient ◽  
Low Velocity ◽  
Flow Noise ◽  
Velocity Flow

Measurements of low‐velocity flow noise on pressure and pressure gradient hydrophones

1979 ◽  
Vol 65 (6) ◽  
pp. 1407-1412 ◽  
Author(s):  
Robert A. Finger ◽  
Louis A. Abbagnaro ◽  
Benjamin B. Bauer
Keyword(s):  
Pressure Gradient ◽  
Low Velocity ◽  
Flow Noise ◽  
Velocity Flow

scholarly journals Analysis of dynamics variation against thixotropic parameter’s preferential range

2018 ◽  
Vol 45 (2) ◽  
pp. 231-251
Author(s):  
Nazish Shahid
Keyword(s):  
Shear Stress ◽  
Pressure Gradient ◽  
Flow Rate ◽  
Axial Velocity ◽  
Fluid Model ◽  
Current Model ◽  
Velocity Shear ◽  
Structural Parameter ◽  
Velocity Flow ◽  
Analysis Of Dynamics

Variation in the dynamics of a steady-state blood flow through a stenosed tapered artery has been investigated corresponding to changes in thixotropic parameter ? over the range [0,1]. To probe the role of parameter ? and differentiate the current model from other known non-Newtonian models, expressions of axial velocity, shear stress, wall shear stress and flow rate have been calculated depending upon this parameter and pressure gradient. Also, pressure gradient has been deduced uniquely with the help of the continuity equation. Our choice of calculating pressure gradient has led to obtaining shear stress such that its dependence on the structural parameter of our model, unlike most available results, motivates for further investigation. The simultaneous effects of varying yield stress and parameter ? on axial velocity, flow resistance and flow rate have been studied such that the differences between the Herschel?Bulkley fluid model and our current model can be pointed out. To validate the suitability of our model and some results in history, we have also obtained limiting results for particular values of ?.

scholarly journals A Portable & Disposable Ultra-Low Velocity Flow Sensor from Bioinspired Hair-Like Microstructures

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 731 ◽  
Author(s):  
Harish Devaraj ◽  
Rajnish Sharma ◽  
Enrico Haemmerle ◽  
Kean Aw
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Modular Design ◽  
Measurement Range ◽  
Flow Sensor ◽  
Design Development ◽  
Low Velocity ◽  
Velocity Flow ◽  
Loop Feedback ◽  
Air Flow Velocity

We present, for the first time, the design, development and testing of a portable ultra-lowvelocity flow sensor with a disposable architecture for use in medical applications. 3Dmicroprintingtechnique was used to fabricate high aspect ratio microscopic hair-like structuresfrom conducting polymers, in particular, poly(3,4-ethylenedioxythiophene):polystyrene-sulfonate(PEDOT:PSS). These high aspect ratio micro-hairs are flexible and conductive that can respond toair flowing over them. A disposable and portable flow sensor with a modular design that allowstuning of measurement range was developed, for integration with an automated neonatalresuscitator to provide closed-loop feedback. The developed portable sensor architecture is capableof real-time indication of the air flow velocity range down to few millimeters/second.

scholarly journals Gravitational Focusing of Low-Velocity Dark Matter on the Earth’s Surface

Galaxies ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 42 ◽  
Author(s):  
Yoshiaki Sofue
Keyword(s):  
Dark Matter ◽  
Solar System ◽  
High Efficiency ◽  
Focal Point ◽  
Flow Speed ◽  
Low Velocity ◽  
The Earth ◽  
Velocity Flow ◽  
Solar System Objects

We show that the Earth acts as a high-efficiency gravitational collector of low-velocity flow of dark matter (DM). The focal point appears on the Earth’s surface, when the DM flow speed is about 17 km/s with respect to the geo-center. We discuss diurnal modulation of the local DM density influenced by the Earth’s gravity. We also touch upon similar effects on galactic and solar system objects.

scholarly journals Dynamic Pressure Gradient Model of Axial Piston Pump and Parameters Optimization

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Shi Jian ◽  
Li Xin ◽  
Wang Shaoping
Keyword(s):  
Pressure Gradient ◽  
Dynamic Pressure ◽  
Parameters Optimization ◽  
Piston Pump ◽  
Opening Angle ◽  
Vertex Angle ◽  
Flow Noise ◽  
Flow Fluctuation ◽  
Large Pressure ◽  
Piston Chamber

The unsteady pressure gradient can cause flow noise in prepressure rising of piston pump, and the fluid shock comes up due to the large pressure difference of the piston chamber and discharge port in valve plate. The flow fluctuation control is the optimization objective in previous study, which cannot ensure the steady pressure gradient. Our study is to stabilize the pressure gradient in prepressure rising and control the pressure of piston chamber approaching to the pressure in discharge port after prepressure rising. The models for nonoil shock and dynamic pressure of piston chamber in prepressure rising are established. The parameters of prepressure rising angle, cross angle, wrap angle of V-groove, vertex angle of V-groove, and opening angle of V-groove were optimized, based on which the pressure of the piston chamber approached the pressure in discharge port after prepressure rising, and the pressure gradient is more steady compared to the original parameters. The max pressure gradient decreased by 70.8% and the flow fluctuation declined by 21.4%, which showed the effectivness of optimization.

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