Conservation Of Mechanical Energy Research Articles

Dynamic Performance Analysis of Gas Film Floating Ring Seals Based on the Reynolds–Bernoulli Small-Perturbation Model

Gas film floating ring seals are extensively utilized in aircraft engines, and precise analysis of gas film performance is crucial for ensuring reliable seal design. For this reason, this paper proposes the Reynolds–Bernoulli small-perturbation (RBSP) model to analyze the performance of the gas film based on the conservation of mechanical energy. Through experimental verification and comparison with other analytical models, the results of the RBSP model calculations are both reliable and more broadly applicable. Analyses using the finite element method revealed that the differential pressure effect of Poiseuille flow and the dynamic pressure effect of Couette flow are the primary factors enabling the floating ring to overcome resistance and establish a non-contact seal. Additionally, an appropriate sealing clearance and an increased width of the floating ring could significantly enhance the dynamic performance of the seal. The research findings offer a dependable performance analysis method for designers of gas film floating ring seals.

Lagrange’s planetary equations with time-dependent secular perturbations

The long-term evolution of quasi-Keplerian systems is driven by a Hamiltonian that is independent of the fast angle. As this Hamiltonian may contain explicitly time-dependent parameters, the conservation of mechanical energy is not guaranteed in such systems. We derive how the semi-major axis evolves in these cases. We analyze two astrophysically interesting examples, those of the harmonic and quadrupole perturbations.

Analisis Pemahaman Konsep Hukum Kekekalan Energi Mekanik Mahasiswa Tadris IPA Pada Mata Kuliah Energi Dalam Sistem Kehidupan

Physics is a branch of science that contains complex explanations regarding the relationships between various natural events which are expressed as facts, theories, concepts, principles and physical laws. Energy is one of essential chapter in physics which contains concepts that need to be understood not memorized. One of the topics discussed in energy material which includes many abstract concepts is the law of conservation of mechanical energy. Studying the law of conservation of mechanical energy, which contains abstract concepts, certainly requires conceptual understanding not just remembering and memorizing. Understanding concepts in physics is very important because it can help develop critical thinking skill, creative thinking skill, and good problem solving skill. The descriptive quantitative method with a test approach was used as a method in this study and the sample is 72 Tadris IPA college students of IAIN Ponorogo in the 3rd semester. The results of the study show that in the category of understanding the concept of the law of conservation of energy in objects moving vertically upwards was classified as moderate, in the category understanding the concept of the law of conservation of energy in objects moving along a certain path was classified as low.

An Ontological Perspective on Mechanical Energy Conservation problem-solving in high School Students

An Ontological Perspective on Mechanical Energy Conservation problem-solving in high School Students

Study the Influence of Impact on the Filled Tube of Aluminum 6082-T6 Alloy by Consideration of Temperature using FEM

In this study, a numerical analysis of the impact behavior of a hollow tube made of aluminum 6082-T6 alloy in accordance with ISO 13314-2011 was conducted using FEM. ANSYS was utilized to execute the simulation procedure utilizing the Explicit Dynamic tool. The geometry of the present study consists of a 900 mm-long tube with a diameter of 60 x 2 mm, which was designed using SpaceClaim in Ansys. The model has meshed with a sweep-type mesh utilizing local coordinates. As a result, quadratic elements were utilized to simulate every impactor effect. The convergence of the mesh was determined in accordance with the equivalent strain analysis. The scope of the inquiry is limited to the mechanical behavior and energy conservation that occurs after the impact technique. The energy that is responsible for each and every sort of energy has been recognized. Instability was observed in both the internal and kinetic energies, with the latter reaching a maximum value of three electro-megajoules. Within each of the three axes, the directional deformation of the tube has been outlined. For a period of forty millimeters, the parallel axis of the impactor has undergone the greatest degree of maximum deformation that it has ever encountered. The equivalent stress, also known as von Mises, was measured in combination with the length of the tube, and it was discovered that it reached its highest point at 450 millimeters at the site of impact with 950 megapascal stresses.

An energy perspective on Galileo’s kinematic paradox

The connection between kinematics and work–energy principles is often not emphasized enough for students to appreciate fully. Highlighting the relationship between the kinematic equations and the conservation of total mechanical energy is crucial. We revisit the solution to Galileo’s kinematic paradox from an energy perspective. Galileo stated that the time it takes for an object to travel from the top to the bottom point of a vertical circle is the same regardless of its path. While mathematical proofs of this statement using kinematic approaches are well-documented, this paper explores the problem from an energy standpoint, using experimental evidence to elucidate the relationship between kinematics and energy.

Cronpes: time measurement device suitable for teaching experimental physics in Brazil

Abstract Several public schools and also universities in Brazil have few or none financial resources to acquire certain equipment for teaching physics. Nevertheless, it is extremely important that institutions, schools and universities offer laboratory conditions for the students, mainly in engineering courses, in order to get the first contact with physics concepts in practice. For this purposes, it was proposed to develop a simple construction, low-cost and easy maintenance photogate (Cronpes) device, so that teachers, technicians and even students from the basic and high education network can build them for their schools, institutions and universities, thus improving the quality of teaching physics. This study aims to implement a photogate Esp32 microcontroller based programmed in MicroPython with good resolution, accuracy and user friendly in order to apply in experiments like simple pendulum, spring oscillations and conservation of mechanical energy. The main focus of this research was to demonstrate, through the development of Cronpes, that we can create solutions for educational laboratories, in a viable, creative and inexpensive way.

Pressure Source Model of the Production Process of Natural Gas from Unconventional Reservoirs

This work is focused on developing a computational model to predict the production rate and pressure evolution of natural gas from unconventional reservoirs, particularly shale gas deposits. The model is based on the principle of conservation of mechanical energy and was developed from the transient solution of Bernoulli’s equation. This solution was obtained by computing the pressure evolution in the well resulting from the combined action of extracting the free gas and of gasification from kerogen. The transient behavior of gas production by hydraulic fracturing was calculated by numerically integrating Bernoulli’s equation. The curves representing gas flow evolution were considered as a series of stepwise steady states under a constant gas flow rate, similar to the pressure–time curves. These time steps were connected by instantaneous drops in pressure or gas flow rates. On the other hand, the delayed release of the adsorbed and dissolved gas in the kerogen was accurately calculated by introducing a semi-empirical gas pressure source term into the gas well pressure equation. The effect of this source is to gradually increase the gas pressure in the reservoir, emulating the gas release mechanisms from the organic matter. Model validation was based on production data from the unconventional reservoirs Eagle Ford, U.S.A., and Burgos basin, México. The initial measured gas production rate was used to determine a global friction factor of the gas flowing out from soil cracks and ducts. Additionally, measured production rate data were used to determine the coefficients of the source term function. Pearson correlation coefficients of 0.97 and 0.96 were obtained for Eagle Ford and Burgos basins data, respectively. In contrast, the corresponding coefficients calculated from the traditional Arps’ model were 0.89 and 0.5, respectively. The present pressure source model (PSM) represents a new approach to characterize the process of gas production from unconventional reservoirs, proving to be accurate in forecasting both the gas flow rate and pressure evolution during gas production. The postulated pressure source term was shown to mimic the desorption and diffusion kinetics, which release free gas from the kerogen.

A Foundational Study on Rational Optimization of Damping Ratio for Accurate Dynamic Simulation with Ultra Large Displacement

The integration of dynamic simulation analysis has become widespread in general-purpose software, providing enhanced capabilities. However, accurately tracking deformations based on complete equilibrium solutions remains a significant challenge in problems characterized by strong geometric nonlinearity. This study examines the accuracy of the combined Newmark β method and Tangent stiffness method in dynamic analysis with ultra large displacements and evaluates the utility of Rayleigh proportional damping in numerical simulations compared to experimental models. An experimental model of a slender steel plate undergoing free vibrations after being released from a deformed state was created. Video footage capturing the deformation histories was compared to computational simulations to verify accuracy. The study also examines the appropriate values of the damping ratio (ζ) and the Newmark β value in the simulations. The results indicate that adjusting various damping ratio and a β value of 1/2 yield more realistic simulations with longer conservation of mechanical energy. The findings suggest that incorporating numerical damping into actual damping settings can achieve a more realistic simulation of dynamic behaviour with ultra-large displacements. Furthermore, experiments and analyses were performed to correct natural frequency by changing Young’s modulus, which is a key factor influencing natural frequencies, with observed correlations to plate thickness, setting the stage for further research under varied conditions to develop a more rational methodology for structural analysis.

Computer-Based Experiment for the Motion of Spring Oscillator on a Linear Air Track Using Ultrasonic Sensor.

In the present paper, an affordable innovative physical experimental equipment consisting of an upper computer, an ultrasonic sensor module, and an Arduino microcontroller has been designed. The relationship between the position of the slider fixed on two springs and time is measured by using the ultrasonic sensor module. A system for slider motion data and image acquisition is constructed by using the LabVIEW interface of Arduino UNO R3. The purpose of this experiment is to demonstrate and interpret the propagation of waves represented by harmonic motion. The spring oscillator system including a slider and two springs is measured and recorded, and the motion can be realized using curve fitting to the wave equation in Sigmaplot. The vibration periods obtained from experimental measurements and curve fitting of the wave equation are 1.130 s and 1.165 s, respectively. The experimental data are in good agreement with the theoretical model. The experimental measurement results show that the maximum kinetic energy is 0.0792 J, the maximum potential energy is 0.0795 J, and the total energy at the position of half the amplitude is 0.0791 J. The results verify the mechanical energy conservation of spring oscillator system in a short time. This self-made instrument has improved the visualization and the automation level of the corresponding experiments.

Thick interface coupling technique for weakly dispersive models of waves

The primary focus of this work is the coupling of dispersive free-surface flow models through the utilization of a thick interface coupling technique. The initial step involves introducing a comprehensive framework applicable to various dispersive models, demonstrating that classical weakly dispersive models are encompassed within this framework. Next, a thick interface coupling technique, well-established in hyperbolic framework, is applied. This technique enables the formulation of unified models across different subdomains, each corresponding to a specific dispersive model. The unified model preserves the conservation of mechanical energy, provided it holds for each initial dispersive model. We propose a numerical scheme that preserve the projection structure at the discrete level and as a consequence is entropy-satisfying when the continuous model conserve the mechanical energy. We perform a deep numerical analysis of the waves reflected by the interface. Finally, we illustrate the usefulness of the method with two applications known to pose problems for dispersive models, namely the imposition of a time signal as a boundary condition or the imposition of a transparent boundary condition, and wave propagation over a discontinuous bathymetry.

An experiment for the study of projectile motion

The classic demonstration experiment of the motion of a point mass thrown at an angle to the horizon is studied. Several measurements of the range of a projectile launched sphere are carried out and compared with the results that were obtained by an analytical approach. The sphere’s motion can be treated as two independent movements, a linear uniform movement in the horizontal direction and a uniformly accelerated motion in the vertical direction. The value of launching velocity obtained by kinematics is compared with those predicted by the law of mechanical energy conservation. The conclusion is that the model of a frictionless sliding sphere is far from explaining the experimental result. The model could be improved proposing that the sphere rolls without sliding (pure rolling) on the platform including the rotational kinetic energy. Finally, the fact that the sphere does not settle completely on the launch rail was considered using an effective radius of rotation. Observed from the three proposed models, the last one is the closest to the obtained experimental value. These activities can also improve students’ understanding of the concept of projectile motion.

Analisis Pengaruh Ketinggian Lintasan Terhadap Gaya Gesek dan Kecepatan Benda Pada Bidang Miring Menggunakan PhET Simulation

Physics is an empirical science, meaning that physics is based on observation and experimentation. One of the fundamental concepts in physics that is the foundation for many calculations is the law of mechanical energy conservation, especially on inclined planes. This study aims to analyze the effect of track height on the friction force and velocity of objects when crossing an inclined plane. This research uses a virtual PhET Simulation laboratory with a virtual experimental research design. This research uses a quantitative approach, the data analysis technique uses statistical methods to determine the effect of track height on the friction and speed of objects. The result of this study is that the height of the track affects the value of the friction force, with increasing track height, the value of the friction force will decrease, this is due to the normal force acting on the inclined plane. In addition, with increasing track height on an inclined plane, the value of mechanical energy will increase. This is because the higher the trajectory, the greater the gravitational potential energy possessed by the object. Keywords: Altitude, Inclined plane, Mechanics, Speed.

ACTIVATION OF STUDENT RESOURCES REGARDING THE WORK-ENERGY THEOREM

Students' understanding of physics will increase along with learning during lectures, but thoughts on this understanding can be flexible and not always permanent, so it is necessary to explore other students' thoughts (resources) that may not have been discussed in previous research. This article focuses on the conceptual analysis of resources, namely the ideas they use in solving problems related to work-energy issues. This research aims to identify the resources used by physics students in work-energy reasoning as a work to explore students' new thoughts that have not been discussed in previous research. The research was conducted on 92 new physics department students in 2023 who took Basic Physics I lectures. Before the test was given, the lecturer gave a short review of the work-energy theorem to remind them of the knowledge they had learned in high school. The results of the research reveal that the resources that are widely used by students are (1) the concept of work in physics which is associated with the understanding of work in everyday contexts, namely as work/work/work, (2) in reasoning about motion phenomena involving potential energy and kinetic energy for students. directly apply the principle of conservation of mechanical energy. It is hoped that these findings will be useful input for lecturers in designing lectures on the topic of work-energy theorem based on resource theory or knowledge in pieces.

Scientific calculation and application of safety marking principles

In today's era, trains have become an indispensable mode of transportation for people, yet safety hazards are inevitable during the process of trains entering stations. To study these safety hazards and the principles behind the design of safety markings, we combine the Bernoulli Effect and the conservation of mechanical energy in fluids, taking into account factors such as a person's weight, volume, and distance from the train. We derive an expression that relates the pressure experienced by individuals to the train's speed, the train's cross-sectional area, the distance between the individual and the train, and the area of the individual subjected to force. By comparing this with the general friction force that corresponds to real-life situations, we find that the distances for safety markings provided by the national "Railway Technical Management Regulations" for high-speed train and dynamic train stations are reasonable: for speeds not exceeding 120km/h, the distance is 1000mm; for speeds over 120km/h but not exceeding 160km/h, the distance is 1500mm; and for speeds over 160km/h up to 200km/h, the distance is 2000mm, regardless of the platform height. Based on the factors affecting the safety markings on railway platforms, four practical safety recommendations are proposed.

Utilization of Video-based Laboratory (VBL) Using Tracker for Analysis of Object Motion on the Laboratory-Scaled Mini Roller Coaster

The use of teaching aids in learning can provide direct learning experiences to students so that learning becomes more meaningful. Students observe physics phenomena that occur and get physics data from these phenomena. The observed physics phenomena often happen very quickly, so it is impossible to record data manually. Therefore, a method is needed to facilitate data recording and analysis. One way to use a video-based laboratory (VBL) is by utilizing a tracker. This method allows for analyzing the objects contained in a video and displays the data in graphs and tables. This study aims to investigate the motion of objects using tracker video analysis on a mini-roller coaster tool. The video analyzed is a video of a solid ball-shaped object with a mass of 8.6 g moving along a roller-coaster trajectory. By tracking an object, physics data will be obtained to analyze acceleration and the law of conservation of mechanical energy. The analysis results match the experimental results and the physics concepts that apply to the roller coaster motion.
 Keywords: video-based laboratory (VBL), tracker, laboratory-scaled mini roller coaster

Sound escapes any gravity well

The principle of mechanical energy conservation limits the height at which a body of mass m and initial total mechanical energy Ei can get in a uniform gravitational field g, namely hmax=Ei/mg . However, the same conservation principle does not pose any limit to the height reachable by a sound wave in a vertical column of (ideal) fluid in the same uniform gravitational field. Here, we provide two accessible proofs of a counter-intuitive result that can represent an amusing digression from the usual presentation of the topic.

Buoyancy and Velocity Field Synergy Principle in Convective Heat Transfer and Its Role in Thermo-Hydraulic Performance Improvement

Abstract This study proposes the buoyancy and velocity field synergy principle and aims to enhance thermo-hydraulic performance in convective heat transfer. A mechanical energy conservation equation concerning synergy between buoyancy and velocity was derived, which describes the mechanical energy transport and dissipation in convective heat transfer. Two new field synergy numbers, FsU,g and FsU,∇p, were proposed to characterize the degree of synergy between velocity and buoyancy, and the degree of synergy between velocity and pressure gradient over the fluid domain, respectively. The pressure drop of a channel subjected to convective heat transfer is related to not only Gr/Re2 but also FsU,g. Under a same Gr/Re2, a larger |FsU,g| leads to a smaller |FsU,∇p|, and thus the pressure drop is decreased. Furthermore, the multifield synergetic relationships among buoyancy, velocity, temperature gradient and pressure gradient were analyzed for convective heat transfer in channels. The correlation between FsU,∇p and (Gr/Re2)FsU,g, and the correlation between FsU,g and a traditional field synergy number characterizing convective heat transfer capability, Fc, were derived, which reveals the coupled mechanisms of mechanical energy dissipation and thermal energy transport in convective heat transfer. The proposed principle was applied in typical channel flows subjected to convective heat transfer, and its benefits were demonstrated. It is noted that both pressure drop reduction and convective heat transfer enhancement can be achieved in convective heat transfer using the proposed principle. This paper provides a new insight for improving thermo-hydraulic performance of heat exchangers.

Analysis of General Cases of Sliding Ladder on Frictionless Surfaces Without Calculus

Theoretical analysis of sliding ladder on a stationary and freely moving wall is presented. The equation of motion and kinematic variables have been derived using Newton’s law and conservation of mechanical energy without calculus. We also plot several kinematic variables versus the angle formed by the ladder and wall. Moreover, we determine the last contact angle at which the ladder loses contact with the wall. This paper investigates four cases of sliding ladder which will be useful for undergraduate students in understanding rotational dynamics.

A new method to design energy-conserving surrogate models for the coupled, nonlinear responses of intervertebral discs

The aim of this study was to design physics-preserving and precise surrogate models of the nonlinear elastic behaviour of an intervertebral disc (IVD). Based on artificial force-displacement data sets from detailed finite element (FE) disc models, we used greedy kernel and polynomial approximations of second, third and fourth order to train surrogate models for the scalar force-torque -potential. Doing so, the resulting models of the elastic IVD responses ensured the conservation of mechanical energy through their structure. At the same time, they were capable of predicting disc forces in a physiological range of motion and for the coupling of all six degrees of freedom of an intervertebral joint. The performance of all surrogate models for a subject-specific L4|\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\vert$$\\end{document}5 disc geometry was evaluated both on training and test data obtained from uncoupled (one-dimensional), weakly coupled (two-dimensional), and random movement trajectories in the entire six-dimensional (6d) physiological displacement range, as well as on synthetic kinematic data. We observed highest precisions for the kernel surrogate followed by the fourth-order polynomial model. Both clearly outperformed the second-order polynomial model which is equivalent to the commonly used stiffness matrix in neuro-musculoskeletal simulations. Hence, the proposed model architectures have the potential to improve the accuracy and, therewith, validity of load predictions in neuro-musculoskeletal spine models.