Showing papers on "Cavity wall published in 2020"
TL;DR: In this article, a moving mesh technique, Arbitrary Lagrangian-Eulerian (ALE) method, is adopted to model the partition displacement and the flow and heat transfer in the enclosure.
49 citations
TL;DR: In this paper, the authors examined the natural convection of the ventilation cavity filled with the Cu−Al2O3−H2O hybrid nanofluid influenced by the effects of the magnetic field.
35 citations
TL;DR: In this paper, the use of the Applied Element Method was investigated and subsequently considered for reproducing the experimentally observed out-of-plane shake-table response of unreinforced masonry full-scale cavity wall specimens subjected to both one-way and two-way bending.
23 citations
TL;DR: In this article, the influence of container dimension constraints on the cavity expansion characteristics were preliminary investigated through series of high-speed water-entry experiments with velocity in the range of 80-470m/s.
22 citations
TL;DR: In this paper, a new type of cavity absorber was designed by first considering its optical performance via a detailed ray-tracing analysis, and then heat transfer enhancements for the cavity wall were explored using the ray tracing-calculated radiative flux.
21 citations
TL;DR: In this paper, the authors use resolvent analysis to determine an unsteady active control setup to attenuate pressure fluctuations in turbulent supersonic flow over a rectangular cavity with a length-to-depth ratio of 6 at a Mach number of 1.4 and a Reynolds number based on cavity depth of 10,000.
Abstract: We use resolvent analysis to determine an unsteady active control setup to attenuate pressure fluctuations in turbulent supersonic flow over a rectangular cavity with a length-to-depth ratio of 6 at a Mach number of 1.4 and a Reynolds number based on cavity depth of 10,000. Large-eddy simulations (LES) and dynamic modal decomposition (DMD) of the supersonic cavity flow reveal the dominance of two-dimensional Rossiter modes II and IV. These predominantly two-dimensional vortical structures generate high-amplitude unsteadiness over the cavity through trailing-edge impingement and create oblique shock waves by obstructing the freestream. To disrupt the undesired formation of vortical structures, we introduce three-dimensional unsteady forcing along the cavity leading edge to generate streamwise vortical structures. Resolvent analysis with respect to the time-averaged base flow is leveraged to determine the optimal combination of forcing frequency and spanwise wavenumber. Instead of selecting the most amplified resolvent forcing modes, we seek the combination of control parameters that yields sustained amplification of the primary resolvent-based kinetic energy distribution over the entire length of the cavity. The sustained amplification is critical to ensure that the selected forcing input remains effective to prevent the formation of the large spanwise vortices. This resolvent-analysis-based flow control guideline is validated with a number of companion LES of the controlled cavity flows. The optimal control setup is verified to be the most effective in reducing the pressure root-mean-square level up to 52% along the aft and bottom cavity walls compared to the baseline cavity flow. The present flow control guideline derived from resolvent analysis should be applicable to flows that require the actuation input to remain effective over an extended region of interest.
19 citations
TL;DR: In this paper, a semi-analytical solution for the quasi-static undrained expansion of a cylindrical cavity in soft soils with fabric anisotropy and structure is presented.
18 citations
TL;DR: In this paper, the effect of different parameters such as Richardson number (between 0.05 and 50), Hartmann number, cavity wall inclination, size and orientation of the T-shaped object on the convective flow features were studied.
Abstract: Mixed convection of carbon-nanotube/water nanofluid in a vented cavity with an inner conductive T-shaped object was examined under pulsating flow conditions under magnetic field effects with finite element method. Effects of different parameters such as Richardson number (between 0.05 and 50), Hartmann number (between 0 and 30), cavity wall inclination (between 0 ∘ and 10 ∘ ), size (between 0.1 H and 0.4 H) and orientation (between −90 ∘ and 90 ∘ ) of the T-shaped object, and amplitude (between 0.5 and 0.9) and frequency (Strouhal number between 0.25 and 5) of pulsating flow on the convective flow features were studied. It was observed that the average Nusselt number enhanced with the rise of strength of magnetic field, solid nanoparticle volume fraction, and amplitude of the pulsation, while the effect was opposite for higher values of Ri number and cavity wall inclination angle. The presence of the T-shaped object and adjusting its size and orientation had significant impact on the main flow stream from inlet to outlet and recirculations around the T-shaped object and in the vicinity of hot wall of the cavity along with the magnetic field strength. Pulsating flow resulted in heat transfer enhancement as compared to steady flow case for all configurations. However, the amount of increment was different depending on the variation of the parameters of interest. Heat transfer enhancements were 41.85% and 20.81% when the size of the T-shaped object was increased from 0.1 H to 0.4 H. The T-shaped object can be utilized in the vented cavity as an excellent tool for convective heat transfer control. As highly conductive CNT particles were used in water, significant enhancements in the average Nusselt number between 97% and 108% were obtained both in steady flow and in pulsating flow cases when magnetic field was absent or present.
14 citations
TL;DR: The seismic performance of existing unreinforced masonry (URM) buildings is considerably affected by typology and level of effectiveness of both construction details and structural components,.
Abstract: The seismic performance of existing unreinforced masonry (URM) buildings is considerably affected by typology and level of effectiveness of both construction details and structural components, espe...
13 citations
TL;DR: The watertightness of solid masonry walls is generally based on the concept of buffering and afterwards drying out the absorbed rainwater as mentioned in this paper, but in cavity walls, on the contrary, the air layer provides a...
Abstract: The watertightness of solid masonry walls is generally based on the concept of buffering and afterwards drying out the absorbed rainwater. In cavity walls, on the contrary, the air layer provides a...
13 citations
TL;DR: In this article, a new Nusselt correlation was developed from an experimental investigation of natural convection heat loss from a non-isothermal scale-model cylindrical cavity receiver.
TL;DR: Cavity walls consisting of an outer leaf, a cavity and an inner leaf are a widespread building enclosure configuration because of their good performance regarding rain tightness as mentioned in this paper. But they do not have the ability to support a large number of occupants.
Abstract: Cavity walls consisting of an outer leaf, a cavity and an inner leaf are a widespread building enclosure configuration because of their good performance regarding rain tightness. To increase the dr...
TL;DR: In this article, an analytical cavity model based on the principle of energy conservation was developed to describe the cavity dynamics in high-speed impacting these "non-infinite" containers, and the hydrodynamic pressure acting on the container wall induced by cavity expansion and the critical size of the container in presence of constraint effects were theoretically analyzed.
Patent•
03 Jan 2020
TL;DR: In this article, an acoustic device which comprises the components of a sound production unit which radiates sound waves at the front side of a vibrating diaphragm to the outside through a sound outlet is described.
Abstract: The invention discloses an acoustic device which comprises the components of a sound production unit which radiates sound waves at the front side of a vibrating diaphragm to the outside through a sound outlet; a first closed cavity is formed in the rear side of the vibrating diaphragm; a mounting hole is formed in the cavity wall of the first closed cavity, a flexible deformation part is arrangedon the mounting hole, a second closed cavity is formed in the outer side of the first closed cavity, and sound waves generated by the flexible deformation part during deformation are closed in the second closed cavity through the second closed cavity; a protective cover plate located on the outer side of the flexible deformation part is further arranged on the mounting hole, and an avoiding spaceused for avoiding vibration of the flexible deformation part is formed between the protective cover plate and the flexible deformation part; the protective cover plate is provided with a plurality ofair-permeable micropores, and the area of each air-permeable micropore is smaller than or equal to 0.2 mm . According to the acoustic device, the resonant frequency can be effectively reduced, and the low-frequency-band sensitivity of the product is greatly improved on the whole.
TL;DR: In this paper, the authors compared the properties of the inner and outer masonry leaves when exposed to the same in-plane drift values and found that cracks in calcium-silicate samples were significantly more likely to split brick units, whereas cracks in the type of clay samples employed, always followed the masonry joints.
Abstract: The north of the Netherlands is prone to frequent, light earthquakes linked to economical losses and societal unrest due to the induced seismicity in the region. These light earthquakes produce correspondingly low values of in-plane drift on the typical masonry structures of the region, many of which are built with cavity walls composed of an inner, load-bearing calcium-silicate masonry leaf, and an outer, exposed fired-clay masonry veneer. To assess the resulting damage from the lighter earthquakes, it is thus necessary to understand the difference in behaviour of the inner and the outer masonry leaves when exposed to the same drift values. Experimental tests of replicated, full-scale calcium-silicate brick walls and spandrels are detailed herein and compared to previously tested clay masonry samples. A purposely developed, scalar damage parameter is used to assess the width, number and length of the cracks to objectively quantify damage. High resolution digital image correlation is used to accurately monitor the initiation and propagation of cracks. The experiments reveal that calcium-silicate samples exhibit slightly greater damage than clay samples when subjected to the same in-plane drift. From the tests, drift values for light damage or ‘damage state one’ are set between 0.15 and 0.65‰ for the type of wall tested. Moreover, in these tests, cracks in calcium-silicate samples were significantly more likely to split brick units, whereas cracks in the type of clay samples employed, always followed the masonry joints. This fundamental difference in the light-damage behaviour between the two materials is of importance when considering the perception of damage, the strategies and cost of the repairs, and the strategies for strengthening of masonry structures with cavity walls resembling the type of masonry tested herein.
TL;DR: In this paper, the influence of choice of initial cavity radius on the soil response during cavity expansion in sandy soil adopting three-dimensional discrete element simulations and obtaining the size of the influence zone when the expansion starts from zero initial radius.
TL;DR: In this article, the Nektar++ method was used to simulate low-speed flow over a two-dimensional cavity at different cavity length-to-depth ratio (R) and freestream Reynolds number (Re).
Patent•
22 May 2020
TL;DR: In this paper, a low-frequency coupling sound absorbing structure, comprising a peripheral cavity (1), a resonant cavity (2) provided in the peripheral cavity, and an extension pipe structure (3) provided inside the resonant cavities, is proposed.
Abstract: A low-frequency coupling sound absorbing structure, comprising a peripheral cavity (1), a resonant cavity (2) provided in the peripheral cavity (1), and an extension pipe structure (3) provided inside the resonant cavity (2). One end of the extension pipe structure (3) is connected to a cavity wall of the resonant cavity (2) by means of a corresponding through hole; the peripheral cavity (1) comprises a micro-perforated plate (11), a back plate (12), a first side plate (13), and a second side plate (14); the micro-perforated plate (11) is provided with a plurality of micro-porous structures (111), the micro-perforated plate (11) is disposed corresponding to the back plate (12), and the first side plate (13) and the second side plate (14) are correspondingly disposed. The low-frequency coupling sound absorbing structure can increase the acoustic impedance of the sound absorbing structure by providing the resonant cavity (2) provided with the extension pipe structure (3) in the peripheral cavity (1) having the micro-porous structures (111), facilitating to increase the sound absorbing coefficient and widen the sound absorbing band, and shift the sound absorbing band to the low frequency, thereby implementing the low-frequency sound absorbing and contributing to the improvement of the product performance.
01 Aug 2020-Microsystem Technologies-micro-and Nanosystems-information Storage and Processing Systems
TL;DR: In this article, the analytical study of translational and rotational motion of a porous spherical particle with quadratically increasing permeability inside a concentric spherical cavity filled with incompressible Newtonian fluid, under the creeping flow conditions was conducted.
Abstract: The present article deals with the analytical study of translational and rotational motion of a porous spherical particle with quadratically increasing permeability inside a concentric spherical cavity filled with incompressible Newtonian fluid, under the creeping flow conditions. The flow fields in clear fluid and porous regions are governed by Stokes equation and generalized Darcy’s law (Brinkman equation) together with mass conservation, respectively. Closed form solutions for translational and rotational mobilities of the particle are obtained with the help of drag and torque acting on the particle surface. The particle mobility inside a cavity attains a maximum value of 1. However, the presence of cavity wall slows down the particle motion as a result the particle mobility becomes smaller than unity. The effect of cavity wall on the mobility is significant when the gap between the particle surface and cavity wall is less. Various limiting cases are obtained which agree with earlier existing results. The results are explained with the aid of graphs for better clarity.
TL;DR: In this paper, the authors applied the incompressible smoothed particle hydrodynamics method for simulating the natural convection flow inside a cavity including cross blades or circular cylinder cylinder.
Abstract: The purpose of this study is to apply the incompressible smoothed particle hydrodynamics method for simulating the natural convection flow inside a cavity including cross blades or circular cylinder cylinder.,The base fluid is water and copper-water nanofluid is treated as a working fluid. The left and rights walls are maintained at a cool temperature, the horizontal cavity walls are isolated and the inner shape was heated. The physical parameters are the length of the blades L_Blade, the number of cross blades, circular cylinder radius L_R, Rayleigh number Ra and the nanoparticles volume fraction.,The results reveal that the lengths of the cross blade, number of the blades and radius of the circular cylinder is working as an enhancement factor for heat transfer and fluid flows inside a cavity. Adding nanoparticles augments heat transfer and reduces the fluid flow intensity inside a cavity. The best case for buoyancy-driven flow was obtained when the inner shape is the circular cylinder at a higher Rayleigh number.,This work uses a distinctive numerical method to study the natural convection heat from cross blades inside a cavity filled with nanofluid. It provides a new analysis of this issue and presented good results.
Patent•
21 Aug 2020
TL;DR: In this paper, a mixing cavity, buffering cavity and buffer cavity are arranged around the mixing cavity in the circumferential direction, and through holes are formed in the cavity wall of mixing cavity and used for communicating the buffer cavity with the mixing cavities.
Abstract: The utility model discloses a surrounding type mixer device which comprises a mixing cavity, a gas inlet pipe, a gas outlet pipe, a gas inlet pipe, a gas outlet pipe, a gas inlet pipe, a gas outlet pipe, a gas outlet pipe and a gas outlet pipe, buffering cavity, the buffer cavity is arranged around the mixing cavity in the circumferential direction, through holes are formed in the cavity wall of the mixing cavity and used for communicating the buffer cavity with the mixing cavity, a circulating waste gas inlet is formed in the buffer cavity, and the through holes are distributed more and moredensely in the circumferential direction of the mixing cavity in the direction from the position close to the circulating waste gas inlet to the position away from the circulating waste gas inlet. Thefarther away from the circulating waste gas inlet, the lower the concentration of the circulating waste gas is, the denser the through holes are distributed, and the denser the through holes can promote the circulating waste gas to enter the mixing cavity. Therefore, the circulating waste gas can uniformly enter the mixing cavity in the circumferential direction of the mixing cavity, so that thefresh air in the mixing cavity can be uniformly mixed with the circulating waste gas. The utility model further discloses a diesel engine.
TL;DR: In this paper, the effects of the insert structural parameters on the characteristics of the cavity, the beam-wave interaction, and the ohmic loss distribution on the cavity walls in a coaxial cavity with a small misalignment of insert are discussed.
Abstract: The coaxial cavity can rarefy the mode spectrum and restrain the mode competition, which is beneficial to the mode selection of high-frequency and high-power gyrotron. However, the misaligned insert would result in frequency shift and a decrease in interaction efficiency. Besides, the ohmic loss on the cavity walls would become uneven, which deteriorates the long pulse operation of the gyrotron. In this article, the effects of the insert structural parameters on the characteristics of the cavity, the beam–wave interaction, and the ohmic loss distribution on the cavity walls in a coaxial cavity with a small misalignment of insert are discussed. An optimal design of coaxial resonator is presented to reduce the influence of a slightly misaligned insert on the output characteristics of the resonator.
Patent•
24 Jan 2020
TL;DR: In this article, the authors present a conference all-in-one machine with a multifunctional angle-adjustable conference all in one machine, which can be adjusted leftwards and rightwards.
Abstract: The utility model relates to the technical field of office appliances. The utility model discloses a conference all-in-one machine, and discloses a multifunctional angle-adjustable conference all-in-one machine. Chassis comprising an opening at the upper end, a working cavity is formed in the bottom of the case; a motor is mounted on the wall of the case; the output end of the motor is connected with a rotating shaft through a coupler; and the other end of the rotating shaft penetrates through the cavity wall of the working cavity, extends into the working cavity and is rotationally connectedwith the cavity wall of the working cavity through a first bearing, the shaft wall, located in the working cavity, of the rotating shaft is symmetrically and fixedly sleeved with driving bevel gears,and fixing plates are symmetrically and fixedly connected to the box bottom in the machine box. The conference all-in-one machine is convenient to transport or move, the occupied space is reduced, thecase protects the display screen, damage to the display screen due to collision is avoided, much dust is prevented from being accumulated on the conference all-in-one machine, the angle of the conference all-in-one machine can be adjusted leftwards and rightwards, and people on the two sides of the display screen can see important information of a conference conveniently.
28 Feb 2020
TL;DR: In this article, the authors present the results of an experimental campaign conducted by the authors on metal wall tie connections and propose a mechanical model to predict the cyclic behaviour of these connections.
Abstract: The seismic assessment of unreinforced masonry (URM) buildings with cavity walls is of high relevance in regions such as in Central and Northern Europe, Australia, New Zealand and China because of the characteristics of the masonry building stock. A cavity wall consists of two separate parallel walls usually connected by metal ties. Cavity walls are particularly vulnerable to earthquakes, as the out-of-plane capacity of each individual leaf is significantly smaller than the one of an equivalent solid wall. This paper presents the results of an experimental campaign conducted by the authors on metal wall tie connections and proposes a mechanical model to predict the cyclic behaviour of these connections. The model has been calibrated by us- ing the experimental results in terms of observed failure modes and force-displacement responses. Results are also presented in statistical format.
TL;DR: In this article, an empirical solution to calculate the average ultimate cavity wall pressure (UCWP) of cavity expansion in undrained clay under anisotropic stress through large deforma...
Abstract: This paper proposes an empirical solution to calculate the average ultimate cavity wall pressure (UCWP) of cavity expansion in undrained clay under anisotropic stress through large deforma...
TL;DR: In this article, the authors numerically explored the mixed convection phenomena in a differentially heated ventilated square cavity with active flow modulation via a rotating plate, and the numerical solution was achieved using Arbitrary Lagrangian-Eulerian (ALE) finite element formulation with a quadrilateral discretization scheme.
Abstract: The present study numerically explores the mixed convection phenomena in a differentially heated ventilated square cavity with active flow modulation via a rotating plate. Forced convection flow in the cavity is attained by maintaining an external fluid flow through an opening at the bottom of the left cavity wall while leaving it through another opening at the right cavity wall. A counter-clockwise rotating plate at the center of the cavity acts as active flow modulator. Moving mesh approach is used for the rotation of the plate and the numerical solution is achieved using Arbitrary Lagrangian-Eulerian (ALE) finite element formulation with a quadrilateral discretization scheme. Transient parametric simulations have been performed for various frequency of the rotating plate for a fixed Reynolds number (Re) of 100 based on maximum inlet flow velocity while the Richardson number (Ri) is maintained at unity. Heat transfer performance has been evaluated in terms of spatially averaged Nusselt number and time-averaged Nusselt number along the heated wall. Power spectrum analysis in the frequency domain obtained from the fast Fourier transform (FFT) analysis indicates that thermal frequency and plate frequency start to deviate from each other at higher values of velocity ratio (> 4).
Patent•
03 Jul 2020
TL;DR: In this article, a method and a device for detecting the compactness of concrete in a prefabricated cavity wall, a readable storage medium, computing equipment and a system is presented.
Abstract: The invention provides a method and a device for detecting the compactness of concrete in a prefabricated cavity wall, a readable storage medium, computing equipment and a system. The concrete compactness in the prefabricated cavity wall is detected based on the infrared technology, the construction quality can be improved, and meanwhile, hidden acceptance is achieved. The method comprises: obtaining a specific infrared image of the single-layer prefabricated cavity wall; wherein the specific infrared image is an infrared image within a preset time range after concrete is poured into the prefabricated cavity wall; determining a first temperature average value corresponding to the specific infrared image; wherein the first temperature average value is an average value of temperatures of a plurality of preset acquisition points in the infrared image; and comparing the temperatures of a plurality of preset acquisition points in the specific infrared image with the first temperature average value, and determining the acquisition points of which the temperature difference values are greater than a preset first threshold value.
Patent•
10 Jan 2020
TL;DR: In this article, the authors proposed an indoor wall cleaning equipment consisting of a shell, wherein the inner upper end of the shell is provided with a cleaning cavity with an upwardopening; the lower side of the cleaning cavity is providing with a collection cavity; the upper side of shell is providing a transmission mechanism for transmitting power to the indoor wall cleaner; and lower side is further providing a lifting mechanism for lifting the indoor cleaning equipment, and a cleaning mechanism for cleaning walls is arranged in the cleaning cavities.
Abstract: The invention discloses indoor wall cleaning equipment. The indoor wall cleaning equipment comprises a shell, wherein the inner upper end of the shell is provided with a cleaning cavity with an upwardopening; the lower side of the cleaning cavity is provided with a collection cavity; the lower side of the shell is provided with a transmission mechanism for transmitting power to the indoor wall cleaning equipment; the lower side of the shell is further provided with a lifting mechanism for lifting the indoor wall cleaning equipment; a cleaning mechanism for cleaning walls is arranged in the cleaning cavity; and a dust collection mechanism for collecting dust intensively is arranged in the collection cavity. The indoor wall cleaning equipment is relatively small in size, and can be operatedin a handheld way. When the indoor wall cleaning equipment works, a cleaning part can be lifted and lowered freely to clean walls at different heights, so that the cleaning range is enlarged. For areas difficult to clean, the cleaning strength for cavity walls can be increased by increasing the rotation speed of the indoor wall cleaning equipment, so that the cleaning efficiency of the indoor wall cleaning equipment is improved greatly.
Patent•
28 Jul 2020
TL;DR: In this paper, the authors proposed a utility model for a filter element and a water purifier, in which the filter element comprises a filter bottle, a filter membrane, filter shell, a piston and a telescopic power piece.
Abstract: The utility model relates to a filter element and a water purifier. Wherein the filter element comprises a filter bottle, a filter membrane, a filter shell, a piston and a telescopic power piece; a filtering cavity and a pressurizing cavity which are communicated with each other are formed in the filtering shell; the filtering membrane is positioned in the filtering cavity; a water outlet of the filtering cavity is communicated with a water outlet of the filtering bottle; the piston is located in the pressurizing cavity and abuts against the cavity wall of the pressurizing cavity in a sealed mode, the telescopic power piece is connected with the piston and used for driving the piston to move back and forth in the pressurizing cavity, the filtering shell is arranged in the filtering bottle,a water passing hole is formed in the portion, forming the filtering cavity, of the filtering shell, and water in the filtering bottle enters the filtering cavity through the water passing hole. Thepressurizing process of the filter cavity communicated with the pressurizing cavity is realized in the process that the piston moves back and forth in the pressurizing cavity, so that the outflow volume of water entering the filter cavity and filtered by the filter membrane is increased, and the flow of the filter element is increased. And the piston for pressurizing is directly arranged in the cavity formed by the filter shell, so that the influence on the overall structure size is small.
Patent•
30 Jun 2020
TL;DR: In this article, a spray cooling device consisting of a radiator, a spray head and a water storage tank is installed in the radiator and the spray head is connected with a water pump.
Abstract: The utility model discloses an automatic liquid spraying and rapid cooling heat dissipation structure for a generator set. The spray cooling device comprises a radiator, a spray cooling mechanism is installed in the radiator and comprises a water storage tank and a spray head, the water storage tank and the spray head are installed at the bottom of the radiator together, and the spray head is fixed to the water storage tank and aligns to the inner cavity wall of the radiator to form an upward spray structure. The upper portion of the water storage tank is of an opening structure and completelycovers the bottom of an inner cavity of the radiator. Spray head is connected with a water pump. According to the utility model, the nozzle is arranged at the bottom of the radiator; the spray head sprays upwards; a spraying angle of 110 degrees is adopted; no-dead-corner spraying of the inner wall of the radiator can be achieved, meanwhile, steam is blown into the periphery of the wall of the exhaust pipe through the fan to achieve further cooling, heat is taken away through cooling liquid and air at the same time, harm of the exhaust temperature to the human body is reduced, the outage rateof a generator set is reduced, safety is improved, and more energy is saved and more environment is protected.