Water-filled Tube Research Articles

Periodic Burst Freezing in a Water-Filled Capillary Tube.

Water-filled porous structures are ubiquitous components in life sciences and engineering. At sufficiently low temperatures, the water inside the porous structures can freeze, triggering the frost heave effect and causing problems such as permafrost, frost damage, and frostbite. In this study, we report a unique pattern of frost heat release through periodic bulging and bursting at the end of a water column inside a capillary tube. When water freezes, it expands in volume and attempts to drain out. However, surface tension can hinder the flow of water, resulting in the formation of a bulge that periodically bursts when the spherical molecule reaches a critical threshold. We determined that the critical contact angle of the bulge is approximately 135°, which is balanced by the surface tension at the three-phase line of contact. The size of the bulge increases nonlinearly with the diameter of the capillary tube, while the number of periodic repetitions is inversely proportional to the tube diameter and directly proportional to the length of the water column. These findings provide insights into the interaction between surface tension and frost heave, which has important implications for the design and optimization of microfluidic devices with improved resistance to freezing.

The dynamic response of a pressure transducer for measurements in water

Dynamic pressure measurements are indispensable in the field of fluid mechanics. Attaching tubing as a transmission line to the pressure transducer is often unavoidable but significantly reduces the usable bandwidth of the measurement system. Complex fluid-wall interactions and potential outgassing of air are present within systems with water-filled tubes. Comprehensive studies aiding researchers in selecting suitable transmission line parameters (i.e., material, length, and diameter) are not available. A simple calibration apparatus is designed for the frequency response characterization of multiple pressure transducers simultaneously applying a pressure step. The setup is thoroughly characterized and a detailed description is provided to optimize the bandwidth. A piezoresistive pressure transducer attached to water-filled tubes, as commonly used in hydrodynamic experiments, is characterized in the low-frequency range (i.e., f≤300\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$f \\le {300}$$\\end{document} Hz). Tube-related effects, such as length, diameter, and material are investigated. The impact of entrapped air within the tubing is analyzed. The feasibility of substituting water with silicone oil to fill the tubes is explored. To optimize the usable bandwidth of the pressure measurement system for dynamic applications, it is essential to maintain short tubing that is as rigid as possible and free from entrapped air. Pressure wave propagation speed is reduced by two orders of magnitude in elastic transmission lines made of silicone. Pressure corrections through dynamic calibration are challenging due to the system’s sensitivity to various parameters affecting the dynamic response.

Synthetic, self-oscillating vocal fold models for voice production researcha).

Sound for the human voice is produced by vocal fold flow-induced vibration and involves a complex coupling between flow dynamics, tissue motion, and acoustics. Over the past three decades, synthetic, self-oscillating vocal fold models have played an increasingly important role in the study of these complex physical interactions. In particular, two types of models have been established: "membranous" vocal fold models, such as a water-filled latex tube, and "elastic solid" models, such as ultrasoft silicone formed into a vocal fold-like shape and in some cases with multiple layers of differing stiffness to mimic the human vocal fold tissue structure. In this review, the designs, capabilities, and limitations of these two types of models are presented. Considerations unique to the implementation of elastic solid models, including fabrication processes and materials, are discussed. Applications in which these models have been used to study the underlying mechanical principles that govern phonation are surveyed, and experimental techniques and configurations are reviewed. Finally, recommendations for continued development of these models for even more lifelike response and clinical relevance are summarized.

Underwater sound absorption characteristics of water-saturated porous materials

In this research, the underwater sound absorption performance of porous media saturated with water is investigated through long straight tubes (LSTs) with circular cross-section and sintered fibrous metals (SFMs) containing complex pores, and effective underwater sound absorption capability is demonstrated theoretically, numerically and experimentally. Specifically, the theoretical model for LSTs, verified by direct numerical simulations (DNSs), reveals that much smaller pore diameter and much larger layer thickness of porous material is needed to gain high waterborne sound absorption coefficient than to obtain large airborne sound absorption coefficient. Besides, to examine the sound absorption capacity of realistic porous materials, SFMs backed with a finite cavity are experimentally measured under 7 different hydrostatic pressures in a water-filled tube, and numerically characterized via multi-physics couplings. Insensitivity of effective sound absorption capability to high pressure is established, which stems from the different underwater wave energy consumption mechanism (i.e. viscous-thermal effect) of porous materials from conventional rubber kind of underwater sound absorption materials. Physically, porous materials possess great potential in developing the next generation of high-performance underwater sound absorption materials.

Topology optimization of chiral metamaterials with application to underwater sound insulation

Chiral metamaterials have been proven to possess many appealing mechanical phenomena, such as negative Poisson’s ratio, high-impact resistance, and energy absorption. This work extends the applications of chiral metamaterials to underwater sound insulation. Various chiral metamaterials with low acoustic impedance and proper stiffness are inversely designed using the topology optimization scheme. Low acoustic impedance enables the metamaterials to have a high and broadband sound transmission loss (STL), while proper stiffness guarantees its robust acoustic performance under a hydrostatic pressure. As proof-of-concept demonstrations, two specimens are fabricated and tested in a water-filled impedance tube. Experimental results show that, on average, over 95% incident sound energy can be isolated by the specimens in a broad frequency range from 1 kHz to 5 kHz, while the sound insulation performance keeps stable under a certain hydrostatic pressure. This work may provide new insights for chiral metamaterials into the underwater applications with sound insulation.

Experimental assessment and numerical simulations of marine fouling effect on underwater sound absorption coatings

Underwater sound absorption coatings capable of absorbing sound energy is essential to conceal underwater vehicles. While the accumulation of marine fouling on surfaces of ship hulls, platforms, and submarines can significantly alter their acoustic properties. Currently, the precise impact that different stages of marine fouling have on underwater sound absorption coatings remains unclear. In this study, a novel lab assessment method was developed to investigate the acoustic effect of marine fouling on the underwater sound absorption coatings. Four distinct stages of marine fouling were artificial fabricated and characterized, including conditioning film, microfouling, medium macrofouling, and heavy macrofouling. These effects are quantified through comprehensive tests conducted in a water-filled impedance tube. It is found that the first two stages of marine fouling have a negligible impact on the underwater sound absorption performance within the low frequency range of 500 Hz and 2000 Hz. While a limited impact is observed in the frequency range of 2000 Hz–5000 Hz, where the sound absorption coefficient remains approximately 0.6. Conversely, in the third and fourth stages of fouling, the average sound absorption coefficient drops from 0.8 to 0.2. Further, a new acoustic finite element method (FEM) model of hard fouling was developed to predict the acoustic effect, and the numerical results show the same trend with the experimental results. These findings emphasize the importance of considering antifouling strategies during the design of underwater sound absorption coatings, with a particular focus on targeting hard fouling organisms as the primary objective.

Comparative dose distribution profiles in a water-filled tube, jet, and tray treated with 1–5 MeV electrons

Accelerated electrons up to 5 MeV energy are relatively low-penetrating, and in the second half of the penetration length, the non-uniformity of energy deposition can increase by 20–50% per 1 mm of material depth. This feature of 1–5 MeV electrons, widely used in technology and research, as well as the high cost of beam power, requires the researcher to have the skills to identify areas of optimal energy deposition and develop measures to reduce energy loss. This work examines the dependence of the average absorbed dose and dose non-uniformity for three modes of electron beam treatment of water, taking into account the beam direction (horizontal or vertical, 1–5 MeV), beam window foil thickness (20–100 μm Al or Ti) and glass wall thickness (0.2–2 mm Pyrex). The dependencies are applicable to clarify, predict and analyze the dose distribution in a liquid irradiated in a tube, jet or tray.

Investigation on Low-Frequency and Broadband Sound Absorption of the Compact Anechoic Coating Considering Hydrostatic Pressure

The anechoic coating capable of absorbing sound energy in low frequencies within broadband is essential to conceal underwater vehicles. However, the geometric deformation and modification of mechanical parameters under hydrostatic pressure affect the prediction of absorption performance in deep water environments. An anechoic coating embedded with tandem resonant voids is proposed in this work to achieve quasi-perfect low-frequency and broadband absorption. The analytical method based on the effective medium approach and numerical simulation are performed to estimate the effects of hydrostatic pressure on sound absorption. When additionally considering the dynamic mechanical parameters of the compressed viscoelastic medium, the original absorption humps in low frequencies are inclined to higher band, accompanied by the expanded absorption bandwidth. Then, the tandem coating specimen is measured in a water-filled impedance tube. The experimental spectra are consistent with the analytical and numerical results under various hydrostatic pressures, demonstrating the efficient absorption (α > 0.7) in broadband low frequencies via ordinary pressure. At the same time, the absorption spectrum under higher hydrostatic pressures is also verified in the tube. Consequently, this work paves the way for a broadband low-frequency underwater absorber design and provides an efficient method to characterize the low-frequency and broadband absorption from the coupled resonant coatings in deep water environments.

Comparison of driven equilibrium and standard spin-echo sequence in MR microscopy: Analysis of signal dependence on RF pulse imperfection and diffusion

Rapid MR imaging of slowly relaxing samples is often challenging. The most commonly used solutions are found in multi spin-echo (RARE) sequences or gradient-echo (GE) sequences, which allow faster imaging of such samples with multiple acquisitions of k-space lines per excitation or imaging with very short repetition times (TRs). Another solution is the use of a spin-echo (SE) sequence superimposed with a driven equilibrium Fourier transform (DEFT) method. Such a (DE-SE) imaging sequence has two refocusing RF pulses that produce two spin-echoes. In the first echo, the signal is acquired from the k-space line, and in the second echo, a 90° RF pulse is applied, typically 180° out of phase with respect to the excitation RF pulse. This last RF pulse allows almost complete magnetization reversal back to the longitudinal orientation with minimal magnetization loss. The DE-SE sequence and its RARE variant are widely used in clinical imaging, but its use in MR microscopy has some peculiarities related to the usually less perfect RF pulse flip angles and diffusion. In this study, their effects are first theoretically analyzed and later verified by experiments on test samples performed on a 9.4 T system for MR microscopy. Experiments on a water-filled tube for TE = 3.4 ms and TR = 25–200 ms showed that the DE-SE sequence produces about 10 times more signal than the SE sequence in this TR range. Finally, the performance of the DE-SE sequence compared to the SE sequence was demonstrated on a biological sample. The presented DE-SE sequence has been shown to be effective for rapid imaging of samples with long T1 relaxation times in MR microscopy and can also be considered as a suitable method for rapid proton density weighed imaging of materials.

Active Control of the Reflection Coefficient of an Underwater Surface

From a strategic point of view, it is essential to protect underwater vehicles from being detected by opponents. Modern mono- or bistatic sonar systems are capable of precisely determining the position of a watercraft. In order to triangulate the positions of watercrafts, the sonar sends out acoustic signals that are reflected by the vehicles’ surfaces. These deflected sound waves are subsequently detected and evaluated. How well an object can be detected using a sonar can be measured according to the target strength. Through their shape, construction and choice of materials, modern underwater vehicles are optimized in relation to minimizing their radiated and reflected sound waves; in this way, their target strength is minimized. These passive measures are particularly effective in the medium- and high-frequency range down to 1500 Hz. To effectively reduce reflections at lower frequencies, an active system is developed in this study and evaluated in a laboratory test with a water-filled impedance tube. The incident sound waves were measured in front of an active surface and then processed using an adaptive control system based on an FPGA platform. The system operates with a very thin piezoceramic applied to the surface in order to minimize the reflections of the sound waves. The laboratory tests showed the high effectiveness of the system under the influence of sonar-like signals.

Ultrafast Axial Freezing in a Liquid-Filled Capillary Tube.

Liquid-filled capillary tubes are a kind of standard component in life science (e.g., blood vessels, interstitial pores, and plant vessels) and engineering (e.g., MEMS microchannel resonators, heat pipe wicks, and water-saturated soils). Under sufficiently low temperatures, the liquid in a capillary tube undergoes phase transition, forming an ice nucleus randomly on its inner wall. However, how an ice layer forms from the nucleus and then expands, either axially or radially to the tube inner wall, remains obscure. We demonstrated, both experimentally and theoretically, that axial freezing along the inner wall of a water-filled capillary tube occurs way ahead of radial freezing, at a nearly constant velocity 3 orders in magnitude faster than the latter. Rapid release of latent heat during axial freezing was identified as the determining factor for the short duration of recalescence, resulting in an exponential rise of the supercooling temperature from ice nucleation via axial freezing to radial freezing. The profile of the ice-water interface is strongly dependent upon the length-to-radius ratio of the capillary tube and the supercooling degree at ice nucleation. The results obtained in this study bridge the knowledge gap between the classical nucleation theory and the Stefan solution of phase transition.

Three-dimensional fluid-structure interaction simulation of the Wheatley aortic valve.

Valvular heart diseases (such as stenosis and regurgitation) are recognized as a rapidly growing cause of global deaths and major contributors to disability. The most effective treatment for these pathologies is the replacement of the natural valve with a prosthetic one. Our work considers an innovative design for prosthetic aortic valves that combines the reliability and durability of artificial valves with the flexibility of tissue valves. It consists of a rigid support and three polymer leaflets which can be cut from an extruded flat sheet, and is referred to hereafter as the Wheatley aortic valve (WAV). As a first step towards the understanding of the mechanical behavior of the WAV, we report here on the implementation of a numerical model built with the ICFD multi-physics solver of the LS-DYNA software. The model is calibrated and validated using data from a basic pulsatile-flow experiment in a water-filled straight tube. Sensitivity to model parameters (contact parameters, mesh size, etc.) and to design parameters (height, material constants) is studied. The numerical data allow us to describe the leaflet motion and the liquid flow in great detail, and to investigate the possible failure modes in cases of unfavorable operational conditions (in particular, if the leaflet height is inadequate). In future work the numerical model developed here will be used to assess the thrombogenic properties of the valve under physiological conditions.

A Spectral Method Algorithm for Modeling the Dispersion of Non-Axisymmetric Modes in Fluid-Filled Elastic Tubes

In order to design a low-noise water-filled pipeline system, it is necessary to obtain knowledge of the dispersion characteristics of axial propagation modes in different water-filled elastic tubes. In this work, an algorithm is developed based on the spectral method, which has previously been used to solve the dispersion of axisymmetric modes in cylindrical structures but has not yet been applied to non-axisymmetric modes. The algorithm can obtain the dispersion characteristics, modal displacement, and stress distribution of axial propagation modes in a fluid-filled elastic multi-layer tube. The algorithm behaves well both at low and ultrasonic frequencies, and it is suitable for any tube dimensions, wall thickness and layers. The results of a water-filled PMMA tube obtained using the spectral method algorithm were verified using a COMSOL simulation, while the dispersion curves of the same tube from the literature were found to be missing some low-order modes. In addition, the dispersion curves of a water-filled three-layer tube are given. The spectral method algorithm has the advantages of fast calculation speed, less computational resources consumed, accurate results, and no modal omission.

A comprehensive analysis of time-dependent performance of a solar chimney power plant equipped with a thermal energy storage system

Solar Chimney Power Plants (SCPP) are among the promising solar thermal electricity generation technologies. Equipped with a Thermal Energy Storage (TES) system, such technologies can overcome variations in the main driving factors such as solar radiation and ambient air temperature. This article presents a comprehensive semi-analytical model of a TES to predict the time-dependent performance of an SCPP. By introducing a Quality Factor of power generation (QF) that includes energy conversion efficiency and capacity factor, the effects of 15 TES materials have been studied on the plant performance. Results indicate no significant difference between water TES and clay or soil type, and water-filled bags or tubes are relatively ineffective in improving performance compared to them. Among the various TES materials analyzed, a type of wet soil, i.e., the specific wet mixture of clay, sand, and silt in closed and dark-colored bags, show excellent performance in both QF enhancement and having low Heat Penetration Depth (HPD) simultaneously. The QF and HPD are directly affected by thermal effusivity and thermal diffusivity, respectively. Implementing wet soil TES for the studied power plant (Manzanares) enhances the QF from 7.46 % (for limestone soil) to 10.95 %. Water-filled bags demonstrate a heat penetration depth of 0.4 m, while wet soil exhibits a slightly greater depth of 0.5 m. Furthermore, water-filled bags experience a broader temperature range of 40 °C, whereas wet soil undergoes a comparatively smaller temperature variation of 26 °C. Furthermore, the capacity factor raises from 41.18 % to 61.07 % when utilizing wet soil TES compared to water-filled bags.

THE EFFECT OF ACCELERATED ABSORPTION OF LIQUID IN A TUBE DURING LASER CAVITATION ON A LASER HEATING ELEMENT

The expansion and collapse of a cavitation bubble during laser heating and subcooled boiling of water in the vicinity of the tip of an optical fiber (laser heating element) installed in a water-filled glass tube with two open ends is studied experimentally and numerically. Cavitation, initiated by continuous laser radiation, is accompanied by the pushing and pulling movement of the heated liquid in the tube and outside it. For the first time, it has been shown that in a tube with an installed laser heating element in a liquid flow moving behind the walls of the bubble, when it collapses at the pole of the bubble surface remote from the end, a liquid jet appears, directed through the bubble to the end of the optical fiber. The jet speeds up the process of sucking liquid into the tube.

Measurement of the transmission loss of a rubber hose

Flexible rubber hoses can provide significant attenuation of vibro-acoustic energy in fluid-filled piping systems. The vibro-acoustic performance of rubber hoses can be measured by using a variation of a water-filled impedance tube, using the two-source method, to determine the impedance and transmission loss. This paper presents the test method and results from measurements performed to characterize the vibro-acoustic behavior of a water-filled, 1.5 m length of DN100 fiber reinforced rubber hose, with beaded and flanged terminations, at two pressures. The test results indicated that the rubber hose test specimen achieved a fluid-borne transmission loss of at least 5-10 dB at low frequencies increasing to more than 45 dB at 1kHz.

Review of scientific instruments: Evaluation of adulteration in honey using a microwave planar resonator sensor.

A microwave microstrip line resonator sensor is developed as an alternative tool for detecting adulteration in honey. A honey-filled tube is placed at the position with the maximum electric field intensity. When the honey is adulterated, its permittivity is changed, leading to a distinct resonance frequency shift and enabling detection. Compared with the existing microwave sensors, this sensor offers the advantages of low cost, compact size, and easy fabrication. Moreover, quantitative analysis of the adulteration could be achieved. Electromagnetic simulation is performed using a co-simulation with CST and MATLAB. The simulation results reveal that the resonance frequency of the resonator decreases as the added water content increases, following a quadratic polynomial relationship. In the experiments, the results demonstrate a successive decrease in the resonance frequency from the empty tube, honey-filled tube to water-filled tube cases. Furthermore, honey samples with varying water contents (up to 70%) are tested, and the resonance frequency decreases with increasing added water content, which agrees well with the simulation results. In addition, there is a quadratic relationship between the two parameters. Principal component analysis is conducted on the transmission coefficients, and the first principal component decreases with increasing water content. With the addition of the second principal component, the cases of different water contents in honey can be well classified.

Effect of Instability Training on Compensatory Muscle Activation during Perturbation Challenge in Young Adults.

Balance requires constant adjustments in muscle activation to attain force steadiness. Creating appropriate training can be challenging. The purpose of this study was to examine the effects of 2 weeks of front squat instability training using a water-filled training tube on force steadiness during an instability challenge. Control (CON, n = 13) and experimental (EXP, n = 17) subjects completed pre- and post-testing for EMG variability by completing one set of 10 repetitions with a stable and unstable training tube. Electrodes were placed bilaterally on the anterior deltoid, paraspinal, and vastus lateralis muscles. CON subjects completed 2 weeks of training using a stable training tube, while EXP subjects trained with a water-filled instability tube. EMG data were integrated for each contraction, and force steadiness was computed using the natural log of coefficient of variation. CON results showed no changes in force steadiness for any condition. EXP showed significant reductions in EMG activation variability across all muscles. These results indicate a significant training effect in reducing muscle activation variability in subjects training with a water-filled instability training device. Improvements seen in these healthy subjects support the development of training implements for a more clinical population to help improve force steadiness.

Performance analysis of triple glazing water flow window systems during winter season

Water is circulated in the space between glazing as part of the Water Flow Window (WFW) technology. This idea may have an impact on the energy consumption of HVAC (heating, ventilation, and air conditioning) equipment. WFW is commonly used to remove excess heat; the excess heat can be stored. The purpose of this study is to compare the performance of triple glazing WFW under environmental conditions of Turkey during the winter. To compare the electrical energy consumption of the HVAC devices of testing cabinets, three identical testing cabinets with three different glazing types; standard (air-filled) window, WFW system with energy storage tank and domestic water supported WFW system are employed. The Thermal Energy Storage (TES) tank is a water tank that contains two distinct Phase Change Materials (PCM). PCMs are positioned all around and crammed inside water-filled pistol-style tubes. The TES tank volume is 5.675 L (42% water, 46% RT18 HC, 12% RT22 HC). The windows' surface area is approximately 0.3 m2. Visualization of the melting process in the TES tank is obtained with the numerical study. Results show that the consumption ratio of cooling devices can fall under 21% for daytime and heating devices can fall under 79% for nighttime.

A lightweight waterborne acoustic meta-absorber with low characteristic impedance rods

We investigate a meta-absorber composed of impedance-matched rods for the broadband acoustic absorption. However, with a slow longitudinal wave speed, the absorber’s density is high to keep the characteristic impedance matching with that of water. To obtain a lightweight high efficiency absorber, we analyze the influence of characteristic impedance and loss factor on absorption behaviors and find that the characteristic impedance matching is not necessary and the low characteristic impedance structure can also attain the efficient absorption performance, and the high dissipation can reduce the density required for an efficient absorption. Based on this, we propose a meta-absorber composed of low characteristic impedance rubber rods in parallel coated by a rubber cover layer and backed with a stepped resin base. By the combination of the transfer matrix method and transmission line impedance transfer equation, the acoustic performance of meta-absorber is analyzed. Compared with the characteristic impedance matching rods, the low characteristic impedance rods can release restrictions on design to attain better acoustic behaviors with a lower density. Further, the integration of rods with designed lengths can motivate coherently coupled weak resonances to obtain a broadband absorption. Finally, an optimized meta-absorber is tested in a water-filled impedance tube and the experimental results agree well with the theoretical results which can achieve a broadband low frequency quasi-perfect absorption (α>0.9) in a deep subwavelength region (λ/158 at 950 Hz) with the density close to that of water. Our work finds a new mechanism that low characteristic impedance absorbing materials can achieve the high efficiency absorption with a slow longitudinal wave speed and low density and promise broad applications in the sound stealth of marine vehicles.