Concepts Of Fluid Dynamics Research Articles

Development of Water Debit Measuring Instruments as Physics Learning Media Using a Flow Meter Sensor

Physics learning aims to ensure that students understand physics concepts completely. Understanding of the concept can be achieved through the help of learning media in the form of teaching aids from physics materials. This research aims to develop learning media for measuring water discharge using a flow meter sensor to improve students' conceptual understanding of dynamic fluid material. This research includes development research through the ADDIE model, carried out until the development stage. Data collection techniques are carried out through the calibration of measuring instruments. The technique for data analysis used is the descriptive analysis of proportions. The study results obtained the following results: 1) The calibration results show that the water discharge measuring instrument as a learning medium has a very small error rate, and 2) The results of the validity assessment obtained by the water discharge measuring instrument have high validity. The water debit measuring instruments can be used to increase understanding of the dynamic fluid material concept. Using this air discharge measuring instrument will help students understand the concept of fluid dynamics, especially in air discharge subjects.

STUDY OF WIND RATE MEASUREMENT IN A VENTURI TUBE SYSTEM EQUIPPED WITH TWO WATER FILLED OPEN MANOMETERS

Various types of physical phenomena are experienced by the wind when it passes through a venturi tube system equipped with two open manometers filled with water. Its theoretical studies lead to 3 equation types of theoretical wind speeds that are unique. Experimental testing of each type of equation as a measurement method is significant to see the suitability level with the concept of fluid dynamics, the precision level, and the accuracy level. The research aims to determine the level of suitability with the fluid dynamics concept, the precision level, and the accuracy level. The research method is an experiment using equipment at the Bandung State Polytechnic Physics Laboratory. The research shows that: The suitability level of the three method measurement results is consistent with the concept of fluid dynamics; The highest level of precision and accuracy is produced by measurement method A, followed by method B, and the lowest by method C; All slopes of the linear curve mean wind speed ( ) is negative, 83.3 % of absolute uncertainty (AU) < 0 (negative), and 83.3 % of relative uncertainty (RU) > 0 (positive); The determination level of va by the diameter variable (d) and the electrical resistance (R) is in a strong category, the determination level of AU by the variable d is in the moderate category but with the variable R is in the weak category and then the weak category for the determination level of RU by the variable d and with the variable R.

Experimental Investigation of Simple-Built and Low-Speed Water Tunnel as a Platform for Studying Fluid Flow Using PIV Measurements

We present a thorough experimental investigation of a simple-built low-speed water tunnel that could facilitate the study of some of the primary fluid dynamic concepts based on quantitative flow measurements using Particle Image Velocimetry (PIV). The water tunnel system is designed and built using a simple arrangement of a double reservoir tank and a centrifugal pump that drives the fluid flow at low speed into a square cross-sectional and relatively short test section. The study shows that the system reasonably and steadily generates fully developed flows inside the test section with <20% of point velocity variations. Based on the fluid-structure tests, it is also observed that the system could produce moderately consistent boundary layer separation phenomena with the variance of the area mean vorticity within 25%. With this performance, we show that the system fulfills the essential requirement to be used as a simple, easy-to-operate, and easy-to-maintain educational platform to study fluid dynamic phenomena related to the interaction of a static sub-merged object and fluid flow.

Interactive Scientific Visualization of Fluid Flow Simulation Data Using AR Technology-Open-Source Library OpenVisFlow

Computational fluid dynamics (CFD) are being used more and more in the industry to understand and optimize processes such as fluid flows. At the same time, tools such as augmented reality (AR) are becoming increasingly important with the realization of Industry 5.0 to make data and processes more tangible. Placing the two together paves the way for a new method of active learning and also for an interesting and engaging way of presenting industry processes. It also enables students to reinforce their understanding of the fundamental concepts of fluid dynamics in an interactive way. However, this is not really being utilized yet. For this reason, in this paper, we aim to combine these two powerful tools. Furthermore, we present the framework of a modular open-source library for scientific visualization of fluid flow “OpenVisFlow” which simplifies the creation of such applications and enables seamless visualization without other software by allowing users to integrate the visualization step into the simulation code. Using this framework and the open-source extension AR-Core, we show how a new markerless visualization tool can be implemented.

Fluid dynamics of cerebrospinal fluid flow in perivascular spaces.

The flow of cerebrospinal fluid along perivascular spaces (PVSs) is an important part of the brain’s system for delivering nutrients and eliminating metabolic waste products (such as amyloid-β); it also offers a pathway for the delivery of therapeutic drugs to the brain parenchyma. Recent experimental results have resolved several important questions about this flow, setting the stage for advances in our understanding of its fluid dynamics. This review summarizes the new experimental evidence and provides a critical evaluation of previous fluid-dynamic models of flows in PVSs. The review also discusses some basic fluid-dynamic concepts relevant to these flows, including the combined effects of diffusion and advection in clearing solutes from the brain.

Using fluid dynamic concepts to estimate species movement rates in terrestrial landscapes

Habitat loss and fragmentation threatens biodiversity and ecosystem function. ‘Permeability’ and ‘connectivity’ indices are used to estimate how individuals, populations or genes move spatially through a landscape. Yet, despite the analogies between landscape permeability and the physical definition of permeability (the ability for a porous media to transport a fluid), there have been few attempts to apply the physical concepts of permeability and fluid flow to problems in landscape movement ecology beyond some simple examples in the early literature. Here, we present a conceptual model linking physical principles to ecological terms and illustrate how concepts from Darcy’s Law of fluid flow through porous media could be used to quantify species movement rates through a heterogeneous terrestrial landscape. Although further refinement is needed to take this concept to two dimensions and into a full predictive model, the approach presented shows promise for quantifying the relative impacts of landscape change (e.g. habitat fragmentation or creation) on species movement rates.

FlowVisual: A Visualization App for Teaching and Understanding 3D Flow Field Concepts

FlowVisual: A Visualization App for Teaching and Understanding 3D Flow Field Concepts

Calculating the ecological impacts of animal‐borne instruments on aquatic organisms

Summary Animal‐borne instruments provide researchers with valuable data to address important questions on wildlife ecology and conservation. However, these devices have known impacts on animal behaviour and energetics. Tags deployed on migrating animals may reduce reproductive output through increased energy demands or cause phenological mismatches of foraging and nesting events. For marine organisms, the only tagging guidelines that exist are based on lift and thrust impacts on birds – concepts that do not translate well to aquatic animals. Herein, we provide guidelines on assessing drag from animal‐borne instruments and discuss the ecological impacts on marine organisms. Of particular concern is the effect of drag from instruments to the welfare of the animals and for the applicability of collected data to wild populations. To help understand how drag from electronic tags affects marine animals in the wild, we used marine turtles as model aquatic organisms and conducted wind tunnel experiments to measure the fluid drag of various marine turtle body types with and without commercially available electronic tags (e.g. satellite, TDR, video cameras). We quantified the drag associated with carrying biotelemetry devices of varying frontal area and design (squared or tear drop shaped) and generated contour plots depicting percentage drag increase as a framework for evaluating tag drag by scientists and wildlife managers. Then, using concepts of fluid dynamics, we derived a universal equation estimating drag impacts from instruments across marine taxa. The drag of the marine turtle casts was measured in wind speeds from 2 to 30 m s−1 (Re 3·0 × 104–1·9 × 106), equivalent to 0·1–1·9 m s−1 in seawater. The drag coefficient (CD) of the marine turtles ranged from 0·11 to 0·22, which is typical of other large, air‐breathing, marine vertebrates (0·08–0·26). The CD of tags in reference to the turtle casts was 0·91 ± 0·18 and most tags caused minimal additional drag (<5%) to adult animals, but the same devices increased the drag for juveniles significantly (>100%). The sensitivity of aquatic animals to instrument drag is a dynamic relationship between the fluid flow patterns, or CD, and the frontal area ratio of the animal and tag. In this paper, we have outlined methods for quantifying the drag costs from animal‐borne instrumentation considering the instrument retention time (time to release from the animal) and the activity of the instrumented animal. With this valuable tool, researchers can quantify the drag costs from animal‐borne instrumentation and choose appropriate tags for their intended study organism and question. Reducing drag will ultimately reduce the impact on the instrumented animals and lead to greater biological realism in the collected data.

State of the Art on Permeability Characterization of Fibrous Reinforcements used in Resin Transfer Molding Process

The physical and mathematical fundamentals that are required for the measurement of permeability of fibrous reinforcement used in Resin Transfer Molding (RTM) and to interpret correctly the results of those experiments are considered in this article. The basic concepts of fluid dynamics through porous media applied to the analysis of the impregnation phenomena in fibre preforms are discussed. The principal assumptions to simplify the governing equations into the Darcy's law are summarized in order to give an idea of some typical features of the permeability tests regarding the injection parameters and types of fluids and preforms used. Three important concepts for determining permeability in any direction for anisotropic preforms are introduced: permeability tensor ( Kij), permeability ellipse and effective permeability ( Keff). This paper also deals with the deduction, from Darcy's law and Laplace Equation, of the basic equations used on the unidirectional and divergent radial permeability tests. The final conclusion remarks the importance of the concepts exposed in this work.

A Preliminary Theoretical Model of Hydrodynamics in the Inner Ear

Head movement should create a transient pressure imbalance across the membranous inner ear. We used basic concepts of fluid dynamics to develop a theoretical model of the inner ear. According to this model, two contiguous fluidic systems-the perilymphatic system and the endolymphatic system-are in hydrostatic equilibrium across a compliant membrane. Our model demonstrates that changes in resistance or compliance in one system results in a transient distortion of the membranous inner ear until equilibrium between the two systems is restored. The concept of hydrodynamic pressure changes in the inner ear has received little attention, but it may represent a new approach to understanding the inner ear and treating inner ear diseases.

Theory from Wind Tunnels: Empirical Roots of Twentieth Century Fluid Dynamics

Wind tunnels became major data-gathering devices for aeronautical engineering. They were indispensible for the design of airships and airplanes (and later also for optimizing the aerodynamic behavior of cars, trains, buildings and bridges). It is not astonishing, therefore, that theoretical concepts of fluid dynamics, too, emerged in close relation to wind tunnel testing. As the scope of fluid dynamics broadened after the Second World War, its roots in aeronautical engineering became obscured. I focus on the relation of the empirical and the formal in boundary layer theory, turbulence research, and gas dynamics. It is rarely remembered that it was in the wind tunnel where the empirical roots of these fields of 20th century fluid dynamics grew in close context with problems of aeronautical engineering.

The overlooked cause of benign prostatic hyperplasia: prostatic urethral angulation

Benign prostatic hyperplasia (BPH) is one of the most common problems faced by aging men and can be associated with bothersome lower urinary tract symptoms that affect quality of life by interfering with normal daily activities and sleep patterns. Despite the clinical importance of BPH, its pathogenesis is still poorly understood. Previously, our understanding of BPH was centered on bladder outlet obstruction being secondary to benign prostatic enlargement. However, prostate size itself is not correlated with the urine flow rate and symptomatology. The prostatic urethra is a bend tube and the increased prostatic urethral angulation shows a higher bladder neck on cystoscopic examination. Although some urologists suspected that the higher bladder neck might be a causal factor for BPH, the clinical significance of prostatic urethral angulation was previously underestimated. In this study, we propose a new hypothesis that prostatic urethral angulation is a causal factor for BPH. By applying the concept of fluid dynamics to the process of urination in the prostatic urethra, we show that the energy loss in this bending tube (the prostatic urethra) can occur during micturition and it increases proportionally to prostatic urethral angulation; this energy loss results in a decrease of the urine velocity and accordingly, the urine flow rate is inversely associated with prostatic urethral angulation. We also propose that BPH involves prostatic urethral angulation as well as the classical BPH triad of prostatic enlargement, bladder outlet obstruction, and symptomatology. Our hypothesis suggests that prostatic urethral angulation is an overlooked cause of bladder outlet obstruction and is a causal factor of BPH, and provides novel insight into the pathogenesis of BPH. Ultimately, the relationship between prostatic urethral angulation and urine flow rate, and other clinical factors including urodynamic parameters, the symptomatology, the response to treatment, and disease progression, need to be investigated in a clinical setting.

Submarine mass-wasting on glacially-influenced continental slopes: processes and dynamics

Abstract Submarine slides and debris flows are common and effective mechanisms of sediment transfer from continental shelves to deeper parts of ocean basins. They are particularly common along glaciated margins that have experienced high sediment flux to the shelf break during and after glacial maxima. During one single event, typically lasting for a few hours or less, enormous sediment volumes can be transported over distances of hundreds of kilometres, even on very gentle slopes. In order to understand the physics of these mass flows, the process is divided into a release phase, followed by break-up, flow and final deposition. Little is presently known regarding release and break-up, although some plausible explanations can be inferred from basic mechanics of granular materials. Once initiated, the flow of clay-rich or muddy sediments may be assumed to behave as a (non-Newtonian) Herschel-Bulkley fluid. Fluid dynamic concepts can then be applied to describe the flow provided the rheological properties of the material are known. Numerical modelling supports our assertion that the long runout distances observed for large volumes of sediments moving down gentle slopes can be explained by partial hydroplaning of the flowing mass. Hydroplaning might also explain the sharp decrease of the friction coefficient for submarine mass flows as a function of the released volume. The paper emphasizes the need for a better understanding of the physics of mass wasting in the submarine environment.

Engineering Applications of Noncommutative Harmonic Analysis: With Emphasis on Rotation and Motion Groups

<i>Engineering Applications of Noncommutative Harmonic Analysis: With Emphasis on Rotation and Motion Groups</i>

120 コンピューターを利用した流体力学実験支援システム

Understanding of fundamental concepts of fluid dynamics in engineering course of university is very important.When students learn physical phenomena in fluid flow, it is very useful to draw the animated flow patterns on. a display by a personal computer.In this paper, two examples of the program for computer aided education, which are coded by the BASIC or FORTRAN, are presented. The first one is a program for drawing 2-dimensional and 3-dimensional pressure distribution in the flow issuing, from a wind tunnel, and the second is interpolation program for data arrangement.By this program, they can understand better for physical phenomena and correct their mistake.

R. Thomas Davis: His contributions to computational fluid dynamics

Attention is given to the contributions of R. Thomas Davis to the general field of computational fluid dynamics (CFD) with particular focus on the numerical simulation of high Re viscous flows. Davis' interest centered on developing solution techniques for the full Navier-Stokes equations by identifying the dominating physics of fluid process and tailoring solution methodologies accordingly. His work covered the spectrum from incompressible to hypersonic speeds, from low to high Re, for 2-D, 3-D and unsteady conditions. A common thread woven throughout his work was that of embedding theoretical fluid dynamic concepts into viscous flow numerical methodology in order to enhance computational efficiency and algorithm robustness, to accelerate iterative convergence, and to reduce truncation errors. It is this theme that he would want carried forward in future CFD research.

Transporterscheinungen in Dreiphasen‐Reaktoren mit fluidisiertem Feststoff

AbstractTransport phenomena in three‐phase reactors with fluidized solids. Three‐phase reactors with fluidized solids have a wide range of application. It extends from catalytic hydrogenation, oxidations, polymerizations, and reactions of synthesis gas to coal liquefaction plant and applications in biotechnology. Considerable advantages of these reactors lie in the intense degree of contact between the phases and in their high thermal stability relative to other types of reactors. Pertinent model concepts of fluid dynamics are treated qualitatively, and our present knowledge about transport phenomena within and between the phases is reviewed. Modelling of these reactors is considered in conclusion.

Longitudinal dispersion of composition differences in the airways of the lung

An analysis is made of longitudinal dispersion of concentration differences in the airways of the lung by applying standard fluid dynamic concepts to the morphometric data of Weibel [21]. Assuming gas of uniform concentration in the “respiratory zones” of the lung “back-mixing” with that in the anatomical dead space, a relationship is derived between P CO 2 at the lips and expired volume closely resembling the CO 2 elimination curve. This is discussed in relation to allowing for dispersion when deriving the true nature of regional and stratified inhomogeneity in the terminal airways.

Investigations into particular human circulatory system phenomena by true computer-man interaction

Recently-developed computer graphic techniques are being applied to certain hemo-dynamic and rheologic problems. Involved are fluid dynamic concepts and numerical analysis techniques. One particular study concerns the simulation of blood flow through prosthetic heart valves in a desire to form an optimum flow design. The investigation has been enlarged to include the study of localisation factors involved in the development of atherosclerotic lesions. Two-dimensional semi-quantitative results showed turbulent motion at, sites of predilection for atherosclerotic plaques. This lends credence to thoughts of turbulence causing injury to the intima and subsequent lesion development. Also formed were preliminary motion studies of idealised heart valve occluders and such simulation compared favourably with clinical findings. These studies have led to shear stress evaluations and the representation of blood flow by particle motion.