Horizontal Plate Research Articles

Scale analysis for water jet impingement over a horizontal flat plate under film boiling configuration

A scale analysis has been performed to investigate the film boiling heat transfer associated with cooling of a horizontal flat plate through water jet impinging. The forced convection film boiling of water is treated by classifying a wide spectrum of subcooling regime by two extreme situations of low and high subcooling dominated by mass evaporation and sensible heating respectively. A simple expression of heat ratio is derived for executing the classification. The ratio is derived by considering the heat and mass transport phenomena and vaporization effect. The radiation heat effect is considered, while obtaining the scale of wall Nusselt number for convective and total heat transfer under both low and high subcooling cases. The comparison of the developed correlations, based on scaling, are made for the wall superheat between 290 and 1100 °C and jet velocity of water between 0.4–3.2 m/s along with the variation of water subcooling between 5 and 45 °C. The proper coefficient of the scaling is developed by making overall comparison of the data from the analysis with experimental data to predict the heat transfer. The effect of liquid to vapor viscosity ratio indicates a substantially higher Nusselt number for the jet impingement of plate under film boiling condition. The density ratio influences the heat transfer only at low subcooling condition. A lower Jakob superheat number, higher Jakob liquid subcooling number, and higher jet Reynolds number increases Nusselt number.

Thermo-Fluid Mechanics of gas-Solid Particle Flows over horizontal Flat Plate

Mathematical model has been developed to protect fluid and solid particle homogeneous mixture velocity concentration and temperature for a heated horizontal flat plate. Conversation equation based on Eulerian scale are approximated for small relaxation times through stream function and similarity transformations. Parametric database generated through computer program for arbitrary constants on comparison with clear fluid reveals the particle concentration has pronounced effect on velocity and temperature profiles.

Numerical Analysis of Geocell Reinforced Square Shallow Horizontal Plate Anchor

This paper presents the uplift behavior of horizontal square anchor in cohesionless soil reinforced with or without geocell in cohesionless soil using three dimensional analyses. The effects of embedded depth ( $$H$$ ), geocell width ( $$B_{g}$$ ), geocell height ( $$h$$ ), geocell pocket size ( $$a$$ ), distance from surface of plate anchor to bottom of geocell ( $$U$$ ), plate anchor width ( $$B$$ ), geocell material stiffness ( $$K$$ ), and relative density of cohesionless soil ( $$D_{r}$$ ) on the dimensionless breakout factor ( $$F_{q}$$ ) and uplift capacity of horizontal plate anchor ( $$Q_{ult}$$ ) were investigated numerically using PLAXIS 3D finite element software with Hardening Soil Model (HSM). The influence of these parameters on the dimensionless breakout factor was discussed and optimum design parameters ( $$B,\frac{{B_{g} }}{B},\frac{h}{B},\frac{a}{B},\frac{U}{B},K$$ ) were determined. Additionally, the results of three dimensional numerical analysis confirmed with those of laboratory indicate that the proposed model is able to capture the uplift load–displacement behavior of geocell reinforced square shallow horizontal plate anchor system in cohesionless soil.

Natural Convection Heat Transfer from Arrays of Different Fin Geometry.(Dept.M)

Natural convection heat transfer from vertical fin arrays of different fin geometry is experimentally investigated. Number, thickness and height of fins are kept constant while base to ambient temperature difference is varied. Experiments are carried out for vertical and horizontal fin array base plate. The Raleigh number is ranged from 2x103 to 8x103. Results showed that the average heat transfer coefficient is greatly affected by the base-to-ambient temperature difference and less affected by the fin geometry and base plate orientation. Over the tested range of Rayleigh number, and with vertical base plate arrays, the straight fin array offered the highest heat transfer coefficient (by a factor of 15% and 10% more than that of unsymmetrical and symmetrical corrugated sin array respectively). An enhancement in the heat transfer coefficient by a factor of about 10 % for the straight fin array more than that of horizontal base plate is also observed and that enhancement is reduced to about 4 and 2% for unsymmetrical and symmetrical corrugated fin array respectively. The effect of both orientation and fin geometry seems to be diminished with the increase of Rayleigh number.

The root growth reduction in response to mechanical stress involves ethylene-mediated microtubule reorganization and transmembrane receptor-mediated signal transduction in Arabidopsis.

We found that mutations in a Ca2+-permeable mechanosensitive channel MCA1, an ethylene-regulated microtubule-associated protein WDL5, and a versatile co-receptor BAK1 affect root growth response to mechanical stress. Plant root tips exposed to mechanical impedance show a temporal reduction in the elongation growth. The process involves a transient Ca2+ increase in the cytoplasm followed by ethylene signaling. To dissect the molecular mechanisms underlying this response, we examined the root growth of a series of Arabidopsis mutants with potentially altered response to mechanical stress after transfer from vertical to horizontal plates that were covered by dialysis membrane as an impedance. Among the plant hormone-response mutants tested, the ethylene-insensitive mutant ein3 was confirmed to show no growth reduction after the transfer. The root growth reduction was attenuated in a mutant of MCA1 encoding a Ca2+-permeable mechanosensitivechannel and that of WDL5 encoding an ethylene-regulated microtubule-associated protein. We also found that the growth reduction was enhanced in a mutant of BAK1 encoding a co-receptor that pairs with numerous leucine-rich repeat receptor kinases to modulate growth and immunity. These results suggest the root growth reduction in response to mechanical stress involves ethylene-mediated microtubule reorganization and also transmembrane receptor-mediated signal transduction.

Vibration suppression of the horizontal flexible plate using proportional– integral–derivative controller tuned by particle swarm optimization

This paper presents the development of an active vibration control for vibration suppression of the horizontal flexible plate structure using proportional–integral–derivative controller tuned by a conventional method via Ziegler–Nichols and an intelligent method known as particle swarm optimization algorithm. Initially, the experimental rig was designed and fabricated with all edges clamped at the horizontal position of the flexible plate. Data acquisition and instrumentation systems were designed and integrated into the experimental rig to collect input–output vibration data of the flexible plate. The vibration data obtained through experimental study was used to model the system using system identification technique based on auto-regressive with exogenous input structure. The plate system was modeled using particle swarm optimization algorithm and validated using mean squared error, one-step ahead prediction, and correlation tests. The stability of the model was assessed using pole zero diagram stability. The fitness function of particle swarm optimization algorithm is defined as the mean squared error between the measured and estimated output of the horizontal flexible plate system. Next, the developed model was used in the development of an active vibration control for vibration suppression on the horizontal flexible plate system using a proportional–integral–derivative controller. The proportional–integral–derivative gains are optimally determined using two different ways, the conventional method tuned by Ziegler–Nichols tuning rules and the intelligent method tuned by particle swarm optimization algorithm. The performances of developed controllers were assessed and validated. Proportional–integral–derivative-particle swarm optimization controller achieved the highest attenuation value for first mode of vibration by achieving 47.28 dB attenuation as compared to proportional–integral–derivative-Ziegler–Nichols controller which only achieved 34.21 dB attenuation.

Push Plate Test of CRTS II Slab Ballastless Track: Theoretical Analysis, Experiments, and Numerical Simulation

Push plate test is a powerful tool to evaluate the interfacial bond performance of China railway track structure type‐II slab ballastless track structure (CRTS II SBTS). However, there is still a lack of theoretical explanation of the push plate test. In this paper, a linear proportional distribution method is proposed in terms of a series of analytical formulas to describe the interfacial force‐displacement variation of CRTS II SBTS in different damage stages of the horizontal push plate test. The force‐displacement relationship established by the linear proportional distribution method agrees well with that observed in full‐scale test. The horizontal push plate test is then simulated, in which a bilinear cohesive zone model (CZM) was adopted to simulate the interface within track structure. The parameters of the CZM are calculated based on the force‐displacement curves obtained from scale push plate test. Particularly, the normal cohesive parameters are determined based on the scale vertical push plate test instead of the traditional splitting tensile test. The simulation proves that both the maximum affected length in the undamage stage and the maximum damaged length in the damage stage depend rather on the interfacial stiffness and the material parameters of SBTS than the horizontal load. These two lengths given by the simulation are close to those defined by the proposed linear proportional distribution method. This indicates the reliability of the proposed method and the capability of scale push plate test in determining cohesive parameters.

Numerical simulation of hydraulic characteristics of surface jet on horizontal base plate with shallow depth

The VOF (volume of fluid) method was applied to track free water surface, and the Realizable turbulent model was used to close the two-phase flow time-averaged equation to numerically simulate the hydraulic characteristics of surface jet on horizontal base plate with shallow depth. The result showed that a big vortex exists in the flow field, and the greater the inlet flow velocity, the longer the length of vortex. The distribution laws of horizontal velocity and longitudinal velocity of a cross section are different in the backflow region and open channel flow region. The gradient decaying of the maximum velocity on cross-section was mainly affected by the inlet velocity.

Estimation of dimensional and qualitative parameters of disk spreader with electric drive

Purpose. Experimental methods to estimate the flight range of mineral fertilizer granules, to determine the shape of the fertilizer scattering torch, to compare the results of practical research with theoretical calculations of the flight range. Methods. Full-scale experimental studies of a mock-up sample of a fertilizer spreader. Results. To improve the quality of sieving, a multi-disc device for sifting mineral fertilizers over the field surface is proposed. It is proposed to make the device in the form of independent, functionally independent modules. Each module consists of three independent units: a fertilizer tank with an agitator; horizontal disc dispenser with calibration holes; a horizontal spreader plate. Each of the modules is equipped with its own electric drive, allowing them to be individually adjusted to a specific operating mode. As a result of studies of a prototype dispenser with active forced-batch dosing of bulk mineral fertilizers, its satisfactory performance was obtained. This makes it possible to regulate the dosage of fertilizers on the spreading disc within the specified limits, and the range of spreading the fertilizers through the individual setting of a certain number of rotational speed of the spreading disc. This arrangement does not limit their number and attachment points on the frame, and the working width of the unit will be regulated only by their number and the range of fertilizer spreading by each individual block. Conclusions. The flight range of mineral fertilizer granules depends on the frequency of rotation of the spreading disc, its height above the surface of the field, and the coefficient of windage of the fertilizers. With a change in the location of the spreading disc height from 0.2 to 1 m, at a spreading disc speed of 46.6; 33.3; 50 s-1, the spreading range for granular superphosphate (double) varies from 1.56 to 7.65 m, granular superphosphate from 1.54 to 7.24 m, granular ammonium nitrate from 1.46 to 6 m. The flight ranges of pellets obtained by practical and theoretical methods coincide within the limits of the requirements. The shape of the resulting spreading spot of fertilizer granules allows, in the case of installing several spreading modules in a line, to obtain fertilizer spreading in the form of an elongated ellipse. Keywords: mineral fertilizers, scatter torch, granules, spreading disc, rotation frequency, flight range.

Non-isothermal Bingham fluid flow between two horizontal parallel plates with Ion-slip and Hall currents

This study presents the numerical solution of velocity and temperature fields based on mass conservation, momentum and energy balances for the time-dependent Couette-Poiseuille flow of Bingham materials through channels. The channel flow of Bingham fluid concerns the flow of cement paste in the building industry and the mudflow in the drilling industry. The specific aim is to introduce the magnetohydrodynamic (MHD) phenomena specified by both Ion-slip and Hall currents into the non-isothermal channel flow in a theoretical approach. The Bingham constitutive equation is formulated by the generalized Newtonian fluid technique and solved by employing the explicit Finite Difference Method (FDM) using the MATLAB R2015a and Compaq Visual FORTRAN 6.6a both. For the exactness of numerical performance estimations, the criteria for stabilization and the convergence factor are analyzed. The velocity and temperature profiles are discussed individually at the moving and stationary walls of the channel. It is observed that magnetohydrodynamic phenomena accelerate the flow, and the temperature distributions reach the steady-state situation earlier than velocity distributions. Furthermore, the dominance of MHD parameters on the velocity distributions, shear stress, temperature distributions, and Nusselt number are discussed.

Seismic details for exterior connections of post-tensioned flat slabs to steel columns using steel plates, vertical stiffeners and bolts

One of the commonly used structural systems in buildings worldwide includes flat slabs supported by steel columns. A key issue in these systems is ductility of the connection between slab and column. Common details for nonprestressed slabs to steel column joints are recommended by well-known references, but specific details for post-tensioned slabs are rarely reported. In this study, specific details have been proposed for connections of post-tensioned flat slabs to steel columns. The details include top and bottom steel plates, vertical stiffeners, and post-tensioned high-strength bolts. To examine the details, a half-scale specimen is subjected to reversed-cyclic loading with increasing amplitude. The test shows that the connection remains elastic up to a drift of 1%, exhibits stable nonlinear response up to a drift of 3.5%, and could tolerate relatively large lateral drifts up to 6% without losing gravity load capacity. The test also indicates that prestressing level, gravity shear force magnitude, and dimensions of horizontal steel plates are important factors that affect seismic behavior of the proposed connection.

対向する水平氷板の温度・濃度複合融解

対向する水平氷板の温度・濃度複合融解

MHD Oldroyd-B Fluid with Slip Condition in view of Local and Nonlocal Kernels

We examine the velocity field of an incompressible Oldroyd-B fluid over a horizontal plate of continual length in a permeable medium with magnetohydrodynamics effect. Firstly, the results for the dimensionless classical model (governing equation) have been studied analytically then the study is extended for different fractional operators. The relations to determine the velocity fields of this problem are found by Laplace transformation and different numerical inversion algorithms. The impact of physical parameters on velocity profiles is analyzed graphically for integer and non-integer models. Non-integer operators are used to analyzing the impact of fractional parameters on the fluid curves of the fluid.

Dynamics of a magnetic pendulum in the presence of an oscillating conducting plate

AbstractA pendulum with an attached permanent magnet moving near a conductor is a typical experiment for the demonstration of electromagnetic braking. When the conductor itself moves, it can transfer energy to the pendulum. We study a simple but exact analytical model where the conductor is a horizontally unbounded flat plate. For this geometry, eddy currents and induced Lorentz force due to the motion of a magnetic dipole are known analytically in the quasistatic limit. A vertical oscillation of such a horizontal plate located beneath the magnet is considered. In this setup, the vertical position of the pendulum is an equilibrium point when the magnetic moment of the magnet is perpendicular to its plane of motion. Depending on the strength of the magnetic dipole moment, the frequency and amplitude of the plate as well as the distance between plate and magnet, the plate oscillation can destabilize the equilibrium. The stability limits for weak electromagnetic coupling are computed analytically using the harmonic balancing method. For stronger coupling, the stability limits are obtained numerically using Floquet analysis. Chaotic motions with finite amplitudes are also found.

Effects of thermal slip and chemical reaction on free convective nanofluid from a horizontal plate embedded in a porous media.

We consider a two-dimensional, uniform, incompressible and free convection flow of a nano-fluid along a plane. The plate is located facing upward about the porous medium. Throughout the investigation, thermal slip, chemical reaction, heat emission/absorption is considered. In the modeling of nano-fluid we have considered the dynamic effect along with the Brownian and thermophoresis. In obtaining the governing equations, including the boundary conditions, an appropriate scaling is applied. The governing momentum equations, including thermal energy and nanoparticles equations are translated into a group of nonlinear ODEs by using Lie symmetry group transformation. The transformed equations are then solved numerically using the Runge-Kutta-Fehlberg fourth-fifth order. The numerical results of velocity, temperature, and nanoparticle volume fraction profiles for varied physical parameters will be discussed and analyzed at the end. The discussion also includes the local Nusselt and the local Sherwood numbers against several of the systems' physical parameters. It is found that the velocity and temperature decrease with thermal slip and heat absorption whilst it increases by increasing heat generation and chemical reaction order. Our present results will be compared with similar existing literature results.

Design equations for prefabricated steel moment connections

Recently, modular prefabricated steel moment connections have been widely studied by several researchers. These connections are made of tubular columns that are ended to horizontal plates at both sides, an inter-story short column, and truss beams that are joined to the connecting plates using top and bottom plates. In this study, a series of equations have been developed and presented for designing each component of this type of connection. Then, to verify the proposed equations, the connection was modeled in ABAQUS and then the results extracted from the equations and modeling were compared. The findings indicated that the proposed equations have the required accuracy.

Applying genetic programming in estimation of frost layer thickness on horizontal and vertical plates at ultra-low temperature

Abstract In this study, the intelligent method of genetic programming (GP) was used for developing predictive models for estimating the frost layer thickness under natural and forced convection on ultra-low temperature surfaces. The affecting dimensionless parameters were used as GP input variables, and realistic empirical correlations were developed for estimating the frost thickness under different conditions. The coefficient of determination of 0.9731, 0.9812, and 0.9906, and average absolute relative error of 6.52%, 11.65%, and 2.87%, were obtained by the developed models for natural convection on vertical plates, natural convection on horizontal plates, and forced convection on horizontal plates, respectively. The physical trends of the developed models were evaluated by comparing the model predictions with the experimental data for different operating conditions, and reasonable agreements were obtained. The same experimental database was also compared to some existing correlations for ordinary-low temperature surfaces, but they failed to provide reasonable estimates for the data.

Wave dissipation over a horizontal slotted plate with a leeside vertical seawall: analytical and numerical approaches

ABSTRACT In this study, the wave energy dissipation over a horizontal slotted plate with a leeside vertical seawall was extensively investigated by analytical and numerical approaches. The analytical model was developed by using the matched eigenfunction expansion method and the energy dissipation model with a porosity-dependent drag coefficient estimated by computational fluid dynamics (CFD) results from the 2D channel flow with symmetric slats. The energy dissipation of a horizontal slotted plate was assessed by analyzing the variation of the reflection coefficient, wave run-up, vertical wave force on the plate, and horizontal wave force on the vertical wall for different submergence depths, porosities, plate lengths, and wave steepnesses. Results from the analytical model were compared extensively with those from CFD simulations. CFD computations were performed by using an incompressible turbulence model based on Reynolds averaged Navier–Stokes equations and volume of fluid method. Overall, a good agreement was observed between the analytical and CFD results. A qualitative numerical analysis showed that the wave dissipation over a horizontal slotted plate was caused by the generation of higher-harmonic waves, wave breaking, and vortices formation near the slotted plate. The presented analytical and numerical models would provide a mutually complementary tool for the accurate and efficient design of a horizontal slotted plate for reducing the reflection coefficients, wave forces, and wave run-up on seawalls.

MHD squeezed Darcy–Forchheimer nanofluid flow between two h–distance apart horizontal plates

Abstract This research is mainly concerned with the characteristics of magnetohydrodynamics and Darcy–Forchheimer medium in nanofluid flow between two horizontal plates. A uniformly induced magnetic impact is involved at the direction normal to the lower plate. Darcy–Forchheimer medium is considered between the plates that allow the flow along horizontal axis with additional effects of porosity and friction. The features of Brownian diffusive motion and thermophoresis are disclosed. Governing problems are transformed into nonlinear ordinary problems using appropriate transformations. Numerical Runge–Kutta procedure is applied using MATLAB to solve the problems and acquire the data for velocity field, thermal distribution, and concentration distribution. Results have been plotted graphically. The outcomes indicate that higher viscosity results in decline in fluid flow. Thermal profile receives a decline for larger viscosity parameter; however, Brownian diffusion and thermophoresis appeared as enhancing factors for the said profile. Numerical data indicate that heat flux reduces for viscosity parameter. However, enhancement is observed in skin-friction for elevated values of porosity factor. Data of this paper are practically helpful in industrial and engineering applications of nanofluids.

WAVE INTERACTIONS WITH SUBMERGED HORIZONTAL FLEXIBLE BREAKWATERS

With the ongoing sea-level rise associated with climate changes, coastline protection is among the top priorities of national interest for many countries across the globe, and particularly those in Southeast Asia with extended shorelines, and submerged horizontal plate breakwaters (SHPB) have been proposed as a possible measure for shoreline protection in the literature. Most of the earlier research works considers the material for the SHPB to be either rigid or elastic sheets (with and without perforations) (Patarapanich, 1984, Heins 1950). The wave modulation due to the presence of such structures is thus predominantly due to wave interactions, edge reflection and turbulence. In this paper, we extend the earlier works and consider the viscoelastic properties for the flexible SHPB (which can better represent the possible damping introduced in the field conditions) both experimentally and analytically.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/l92umh2KnYY