scholarly journals An experimental approach to the fundamental principles of hemodynamics

2005 ◽  
Vol 29 (3) ◽  
pp. 165-171 ◽  
Author(s):  
Francisco Pontiga ◽  
Susana P. Gaytán
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Experimental Approach ◽  
Experimental Setup ◽  
Simple Construction ◽  
Vascular Networks ◽  
Hands On ◽  
Series Of Experiments ◽  
Physical Variables ◽  
The Relationship

An experimental model has been developed to give students hands-on experience with the fundamental laws of hemodynamics. The proposed experimental setup is of simple construction but permits the precise measurements of physical variables involved in the experience. The model consists in a series of experiments where different basic phenomena are quantitatively investigated, such as the pressure drop in a long straight vessel and in an obstructed vessel, the transition from laminar to turbulent flow, the association of vessels in vascular networks, or the generation of a critical stenosis. Through these experiments, students acquire a direct appreciation of the importance of the parameters involved in the relationship between pressure and flow rate, thus facilitating the comprehension of more complex problems in hemodynamics.

Experimental Characterization of Aerosol Production, Transport, Vaporization, and Atomization Systems. Part I: Factors Controlling Aspiration Rates

1985 ◽  
Vol 39 (6) ◽  
pp. 916-920 ◽  
Author(s):  
R. K. Skogerboe ◽  
S. J. Freeland
Keyword(s):  
Pressure Drop ◽  
Flow Rate ◽  
Gas Flow ◽  
Present Knowledge ◽  
Experimental Characterization ◽  
Gas Flow Rate ◽  
Factors Affecting ◽  
Simple Linear Equation ◽  
The Relationship

This paper describes the results of the first stage of an investigation designed to extend present knowledge of the factors affecting aerosol production, transport, vaporization, and atomization in analytical spectroscopy systems. It focuses on factors controlling aspiration of aqueous solutions. The results demonstrate that the effect of gas flow on the pressure drop induced at the tip of the solution draw tube can be described by a simple linear equation; that the relationship between gas flow rate and solution nebulization rate can also be modelled by a simple equation; and that these relationships are not adequately represented by the Hagen-Poiseulle equation, as is often claimed.

Non-Linear Filtration Through Stratified Porous Media: An Experimental Approach to Model the Volumetric Flow Rate and Pressure Drop Relationship

2021 ◽  
Author(s):  
Ashes Banerjee ◽  
Srinivas Pasupuleti ◽  
Vasant Govind Kumar Villuri ◽  
Abhay Kumar Pushkar ◽  
Rajesh Nune ◽  
...  
Keyword(s):  
Porous Media ◽  
Pressure Drop ◽  
Flow Rate ◽  
Experimental Approach ◽  
Volumetric Flow Rate ◽  
Non Linear ◽  
Linear Filtration

scholarly journals Analysis of the Structure and Hydraulic Function of Bordered Pits Using the Lattice Boltzman Method

Forests ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 526
Author(s):  
Wen Qu ◽  
Chunmei Yang ◽  
Yan Ma ◽  
Wenji Yu ◽  
Guangyi Qin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Pressure Drop ◽  
Flow Field ◽  
Flow Rate ◽  
Complex Structure ◽  
Macroscopic Model ◽  
Aperture Diameter ◽  
Bordered Pit ◽  
Bordered Pits ◽  
The Relationship

Fluid flow between adjacent tracheids is realized through bordered pits in the xylem of conifers. The pit has an extremely small size and a highly complex structure. This paper presents a mesoscopic analytical method for the relationship between the pit structure and its hydraulic characteristics through mathematical modeling using the lattice Boltzmann method (LBM) and curved boundary treatment. Mongolian Scots pine were selected as the research subject of this study, and the bordered pit structure parameters was collected by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and the original geometric features were maintained for direct modeling analysis. The model revealed the relationship between various components of the bordered pit and liquid flow velocity/resistance, indicating that margo is the main factor affecting flow resistance. Further anatomical investigation separately analyzed the influence of change in a single factor, including pit diameter, pit aperture diameter, pit depth, torus diameter, and margo thickness, on the overall flow and pressure drop to confirm the importance of various factors in this relationship. Additionally, the influence of pore size and pore location distribution in the margo on the flow rate and pressure drop was further analyzed quantitatively. The results showed that the flow rate through individual pores is the result of the combined effect of pore area and radial position of the pore in the margo. Our study promotes the research and application of the mesoscopic model LBM in simulating flow conditions in the complex flow field of pits, which realizes the numerical analysis of the flow field model based on individualized real bordered pits. In comparison with the classical macroscopic model, the accuracy and effectiveness of the proposed model are proved. This research can provide a promising method for analyzing the physiological and ecological functions of conifer and realizing the efficient utilization of wood resources.

The Pad and Quad Resistors - Two New Methods of Fluid Flow Measurements

1976 ◽  
Vol 190 (1) ◽  
pp. 205-214 ◽  
Author(s):  
S. A. Morsi
Keyword(s):  
Fluid Flow ◽  
Pressure Drop ◽  
Flow Rate ◽  
High Capacity ◽  
Flow Measurements ◽  
Output Pressure ◽  
Multi Stage ◽  
New Type ◽  
The Relationship ◽  
Single Configuration

This paper describes two methods of fluid flow measurements of the differential pressure type. The first method uses a new type of linear resistor in which the flow rate is linearly proportional to the pressure drop. This linear resistor, called a pad-resistor, may be used in a single configuration when the flow rate is limited to small values. For a flowmeter of high capacity and low resistance a multi-pad multi-stage configuration, where several pad-resistors are connected in parallel, has been adopted. The second method uses a non-linear resistor called a quad-resistor. This type of resistor has a flow characteristic proportional to the fourth order of the pressure drop. By combining the quad-resistor with an orifice, the relationship between the pressure drop and the flow rate becomes approximately linear. The quad-resistor has been used in conjunction with a fluidic analogue amplifier to give a linearized output pressure proportional to the flow rate in a fluid duct.

Study of fluid flow through a channel deformed by piezoelement

2018 ◽  
Vol 13 (3) ◽  
pp. 1-10 ◽  
Author(s):  
I.Sh. Nasibullayev ◽  
E.Sh Nasibullaeva ◽  
O.V. Darintsev
Keyword(s):  
Fluid Flow ◽  
Pressure Drop ◽  
Boundary Conditions ◽  
Flow Rate ◽  
Contact Surface ◽  
Piezoelectric Element ◽  
Neumann Boundary ◽  
Differential Pressure ◽  
Physical Parameters ◽  
Flow Through

The flow of a liquid through a tube deformed by a piezoelectric cell under a harmonic law is studied in this paper. Linear deformations are compared for the Dirichlet and Neumann boundary conditions on the contact surface of the tube and piezoelectric element. The flow of fluid through a deformed channel for two flow regimes is investigated: in a tube with one closed end due to deformation of the tube; for a tube with two open ends due to deformation of the tube and the differential pressure applied to the channel. The flow rate of the liquid is calculated as a function of the frequency of the deformations, the pressure drop and the physical parameters of the liquid.

An improved de Laval nozzle experiment

2021 ◽  
pp. 030641902110341
Author(s):  
Nicholas Goodman ◽  
Brian J Leege ◽  
Peter E Johnson
Keyword(s):  
Data Acquisition ◽  
Laval Nozzle ◽  
Flow Characteristics ◽  
Data Acquisition System ◽  
Isentropic Flow ◽  
Hands On ◽  
De Laval Nozzle ◽  
Physical Phenomena ◽  
The Impact ◽  
The Relationship

Exposing students to hands-on experiments has been a common approach to illustrating complex physical phenomena that have been otherwise modelled solely mathematically. Compressible, isentropic flow in a duct is an example of such a phenomenon, and it is often demonstrated via a de Laval nozzle experiment. We have improved an existing converging/diverging nozzle experiment so that students can modify the location of the normal shock that develops in the diverging portion to better understand the relationship between the shock and the pressure. We have also improved the data acquisition system for this experiment and explained how visualisation of the standing shock is now possible. The results of the updated system demonstrate that the accuracy of the isentropic flow characteristics has not been lost. Through pre- and post-laboratory quizzes, we show the impact on student learning as well.

scholarly journals Hot Box Investigations of a Ventilated Bioclimatic Wall for NZEB Building Façade

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1327
Author(s):  
Dwinanto Sukamto ◽  
Monica Siroux ◽  
Francois Gloriant
Keyword(s):  
Energy Efficiency ◽  
Flow Rate ◽  
Experimental Setup ◽  
Air Flow Rate ◽  
Space Thickness ◽  
Zero Energy ◽  
Interior Space ◽  
Air Space ◽  
Thermal Metrology

The building sector is the largest consumer of energy, but there are still major scientific challenges in this field. The façade, being the interface between the exterior and interior space, plays a key role in the energy efficiency of a building. In this context, this paper focuses on a ventilated bioclimatic wall for nearly zero-energy buildings (NZEB). The aim of this study is to investigate an experimental setup based on a hot box for the characterization of the thermal performances of the ventilated wall. A specific ventilated prototype and an original thermal metrology are developed. This paper presents the ventilated prototype, the experimental setup, and the experimental results on the thermal performances of the ventilated wall. The influence of the air space thickness and the air flow rate on the thermal performances of the ventilated wall is studied.

scholarly journals Neural network-based modeling of the number of microbubbles generated with four circulation factors in cardiopulmonary bypass

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Satoshi Miyamoto ◽  
Zu Soh ◽  
Shigeyuki Okahara ◽  
Akira Furui ◽  
Taiichi Takasaki ◽  
...  
Keyword(s):  
Cardiopulmonary Bypass ◽  
Flow Rate ◽  
Neurological Complications ◽  
Estimation Accuracy ◽  
Model Parameters ◽  
Perfusion Flow ◽  
Postsurgical Complication ◽  
Tenfold Cross Validation ◽  
Suction Flow ◽  
The Relationship

AbstractThe need for the estimation of the number of microbubbles (MBs) in cardiopulmonary bypass surgery has been recognized among surgeons to avoid postoperative neurological complications. MBs that exceed the diameter of human capillaries may cause endothelial disruption as well as microvascular obstructions that block posterior capillary blood flow. In this paper, we analyzed the relationship between the number of microbubbles generated and four circulation factors, i.e., intraoperative suction flow rate, venous reservoir level, continuous blood viscosity and perfusion flow rate in cardiopulmonary bypass, and proposed a neural-networked model to estimate the number of microbubbles with the factors. Model parameters were determined in a machine-learning manner using experimental data with bovine blood as the perfusate. The estimation accuracy of the model, assessed by tenfold cross-validation, demonstrated that the number of MBs can be estimated with a determinant coefficient R2 = 0.9328 (p < 0.001). A significant increase in the residual error was found when each of four factors was excluded from the contributory variables. The study demonstrated the importance of four circulation factors in the prediction of the number of MBs and its capacity to eliminate potential postsurgical complication risks.

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