Mecanica de los Fluidos Research Papers (original) (raw)

El presente artículo realiza una breve descripción sobre los modelos matemáticos de viscoelasticidad más simples: Modelo de Maxwell y Modelo de Kelvin-Voigt. No obstante, estos modelos básicos poseen una serie de limitaciones ya que se desvían de forma considerable de la realidad. Así pues, un modelo más apropiado en el estudio de la viscoelasticidad en polímeros es el modelo de Burgers. Mediante la resolución de un caso práctico se pone de manifiesto la utilidad de los modelos matemáticos en la comprensión y predicción por parte del alumnado del comportamiento mecánico de un polímero en un proceso como la fluencia y/o relajación donde interviene la variable tiempo. The present article makes a brief description about the simplest mathematical models of viscoelasticity: Maxwell Model and Kelvin-Voigt Model. However, these basic models have a number of limitations because it has considerable differences from reality. Thus, the Burgers model is studied due to is an appropriate model to study the viscoelasticity in polymers. By solving a practical case, the usefulness for students of mathematical models related with process such as creep or relaxation and their understanding and prediction of the mechanical behaviour has been revealed.

ABSTRACT: Magnetorheological fluids (MRF) are increasingly used for the design of dampers in many cases when a given response is critical for desired performance. Some recent examples are self-powered magnetorheological dampers, cable vibration control and wheeled vehicle dampers. Loads of this type can be very big, especially in the case of seismic-dampers as well as in heavy vehicles and aircraft landing gear. This problem can be more efficiently dealt with by using an inverse-problem strategy, where the required performance is specified a priori, and the fluid parameters are changed accordingly by means of a variable magnetic field. The effect on the flow of the time-variation of the parameters of the Herschel-Bulkley constitutive model is analyzed in this paper. In this way, the influence of a varying magnetic field on the unsteady flow of a magnetic fluid is explored. Yield stress, viscosity and power index are assumed time-dependent. In particular, linear variations in time of these parameters are considered, and the case where the yield stress and viscosity oscillate in time is explored in detail. The characteristics of the velocity field are analyzed for different values of the constants that determine the time structure of the constitutive parameters.

ABSTRACT: Accurate measurement of permeability is critical for fluid flow modeling in porous media. Various experimental methods devised to measure permeability as a porous material property in composites are reviewed. Liquid flow and gas flow methods of permeability measurement for in-plane and transverse directions specifically for fiber-reinforced composites are discussed, as well as issues related to these methods and some associated permeability models. Alternative methods of permeability determination based on cross transport phenomenon are reviewed as well.

ABSTRACT: Steady two-dimensional natural convection in fluid filled cavities is numerically investigated for the case of non- Newtonian shear thickening power law liquids. The conservation equations of mass, momentum and energy under the assumption of a Newtonian Boussinesq fluid have been solved using the finite volume method for Newtonian and non-Newtonian fluids. The computations were performed for a Rayleigh number, based on cavity height, of 10(exponent 5) and a Prandtl number of 100. In all of the numerical experiments, the channel is heated from below and cooled from the top with insulated side-walls and the inclination angle is varied. The simulations have been carried out for aspect ratios of 1 and 4. Comparison between the Newtonian and the non-Newtonian cases is conducted based on the dependence of the average Nusselt number on angle of inclination. It is shown that despite significant variation in heat transfer rate both Newtonian and non-Newtonian fluids exhibit similar behavior with the transition from multi-cell flow structure to a single-cell regime.

- by Dennis A . Siginer
- •
- Engineering, Engineering Physics, Mechanical Engineering, Chemical Engineering
- by Dr. Binama Maxime
- •
- Computational Fluid Dynamics, Fluid Mechanics, Rheology, Fluid Dynamics
- by Mecatrônica Unip - Turma 02/2014
- •
- Mecanica de los Fluidos, APS

The purpose of prototyping is to validate the material and geometrical shape of the design created for a product. The properties and quality of the prototype created plays a vital role in validating the design. The selection of an appropriate process parameters for making the prototype has more influence over the mechanical properties and quality characteristics of the finished prototype. In other words, the success and market life of a product entirely relies upon the prototyping results. Rapid prototyping techniques generally involve numerous process parameters which need to be optimized to build a prototype with superior performance. Fused deposition modeling is one of the familiar and fascinating RP technique which has gained interest in the field of prototyping products of Engineering, Architecture, Medical, Automotive and Aerospace due to its simplicity and flexibility in creating conceptual models and functional parts with desired quality. In the present work Impact Hammer testing of FDM processed PolyEthylene Terephthalate Glycol-modified(PET-G) and Acronitrile Butadiene Styrene (ABS) plastics is conducted to observe the influence of FDM process parameters. The major FDM parameters such as Infill Density (ID), Layer Thickness (LT) and Printing Speed (S) are considered to obtain Frequency Response Function (FRF) for PET-G and ABS plastics. The test results have shown considerable changes in vibration properties (Frequency and amplitude) in both the materials. A 23 (2 Levels, 3 Factors) design L4 Orthogonal Array is created using Minitab 17.0 is used for conducting the experiments.

- by Marcell Bello
- •
- Mecanica de los Fluidos
- by Carmen Mejía
- •
- Física, Mecanica de los Fluidos, Trabajo
- by Pedro Ivens
- •
- Mecanica de los Fluidos

En nuestro diario vivir, inconscientemente nos encontramos interactuando con un fluido, por ejemplo, cuando respiramos estamos inhalando y exhalando el aire de la atmósfera, que es un fluido en estado gaseoso, o cuando bebemos agua, estamos interactuando con un fluido en estado líquido, pero también lo hacemos cuando caminamos, corremos, nadamos, saltamos, sudamos, y un sin número más de actividades que podamos realizar, por tanto, sin importar donde vayamos en el planeta, y la actividad o el trabajo que realicemos, siempre estaremos interactuando con un fluido.

- by Kevin Toala Vite
- •
- Fluid Mechanics, Applied Mechanics, Mecanica de los Fluidos

Una monografía manuscrita sobre la cinemática y la dinámica de boomerangs de dos brazos iguales presentada para el diseño de boomerangs cambiando los parámetros de diseño como los son el tamaño, el perfil aerodinámico, el alabeo, el material de fabricación, la velocidad angular inicial, la velocidad de lanzamiento inicial, etc. La propiedades geométricas, físicas y dinámica del boomerang son establecidas numéricamente basadas en la integración mediante el Teorema de Pappus generalizado. De igual forma se calculan las fuerzas y momentos en cada instante, observándose el efecto giroscópico en la dinámica del vuelo del cuerpo rígido, siguiendo los ángulos de Euler. La ecuaciones de movimiento del boomerang se establecen como un sistema de ecuaciones diferenciales ordinarias temporales, que integradas resultan en la descripción de la trayectoria circular en cada instante desde el lanzamiento hasta el aterrizaje. Los perfiles aerodinámicos utilizados son del tipo NACA de cuatro dígitos e incluyen la sustentación y al arrastre. Contiene al final unas pautas para el diseño aproximado del boomerang.

- by Andrés L . Granados M.
- •
- Aeronautical Engineering, Mecanica de los Fluidos, Mecanica

Flujo de fluidos compresibles

- by Harold martinez fernandez
- •
- Mecanica de los Fluidos
- by Roberto Moises Sanchez Roman
- •
- Mecanica de los Fluidos
- by Yanett del Pilar Tapia Díaz
- •
- Mecanica de los Fluidos

Introducción a la teoría de la capa límite. Incluye capa límite laminar y capa límite turbulenta. Se hace un tratamiento específico para capas límites exteriores y capa límites interiores bajo una formulación integral.

- by Andrés L . Granados M.
- •
- Mecanica de los Fluidos
- by Alejandro Palpan Flores
- •
- Mecanica de los Fluidos, Universidad, Hidrologia, Infiltration
- by juan Sandoval
- •
- Mecanica de los Fluidos

Principios de la ecuación de Bernoulli, aplicaciones y esquema del montaje experimental

Prinsloo, G.J. 2011. Inlet Air Flow Meter for an Internal Combustion Engine. Bachelor Engineering Thesis, Mechatronic Engineering, Stellenbosch University, South Africa. doi 10.13140/2.1.3010.4649.
This project focus on the design an Inlet Air Flow Meter for accurate measurement of mass flow rate of atmospheric air into an engine during engine dynamometer tests. The meter will be used to determine the air-fuel ratio and volumetric efficiency of the engine. To determine if an Inlet Air Flow Meter can be designed and constructed to be sufficiently accurate for dynamometer applications, while evaluating the potential for commercial use in high performance engine management systems. The Inlet Air Flow Meter will be used to evaluate new Biofuel formulations and their performance in internal combustion engines, for example non-edible vegetable oils extracted for fatty acid compositions and biodiesel production, and to evaluate the air flow characteristics, engine performance and emissions production of non-edible oils.

- by Gerro Prinsloo
- •
- Engineering, Electrical Engineering, Mechanical Engineering, Robotics

In the development of transport equations the use of the Reynolds Transport Theorems is fundamental. In general, these theorems have been deduced based on kinematical arguments and the definition of derivatives. In this paper a new viewpoint is examined. The Generalized Leibniz Rule for ℝⁿ domains is completely deduced, including the Euler Generalized Dilatation Formula. Extensions of the Leibniz Rule with special formulations for conservative functions, singular and interface hypersurfaces are also presented. The Leibniz Rule is particularized for ℝ² and ℝ³ domains. The first important application of the particular Leibniz Rule is made for a domain composed of a continuous material systems flowing in a three dimensional space generating the traditional First Reynolds Transport Theorem. The Second Reynolds Transport Theorem is deduced by the application of the Leibniz Rule for ℝ³ together with the First Reynolds Transport Theorem. The Third Reynolds Transport Theorem is obtained dealing with density as a conservative function. The second important application is made for a domain composed of a two-phase material system with a singular or interface surface that permits the flow of mass through itself. In these cases the surface is a two dimensional curved space immersed in ℝ³, where the functions have discontinuity. The metric for this curved space is introduced into the equations and its evolution in time is physically interpreted with the inclusion of the velocity field. The third important application is made for the Conservation Principles. This includes the Conservation Equation and the Jump Condition formulations. Additionally, all Conservation Laws for Mass, Linear Momentum, Angular Momentum, Energy and Entropy are summarized in tabular form. Finally, the results of this paper are compared with those recently reported.

- by Benslimane Hakim
- •
- Fluid Mechanics, Fluid Dynamics, Fluids, Mecanica de los Fluidos
- by robert james rivera gomez
- •
- Mecanica de los Fluidos
- by Tomas Rossi
- •
- Mecanica de los Fluidos, Mecánica de fluidos

Ejercicios resueltos de campo de velocidad y gradiente de presión.

- by Kevin Toala Vite
- •
- Fluid Mechanics, Fluid Dynamics, Mecanica de los Fluidos
- by Benslimane Hakim
- •
- Fluid Mechanics, Fluid Dynamics, Fluids, Mecanica de los Fluidos

Para una presión manométrica en A de-0.11 Kg/cm², encontrar la densidad relativa (Dr) del líquido manométrico B de la figura. Solución.

- by Hugo Alexander Tipula Torres
- •
- Mecanica de los Fluidos
- by Saker Bel
- •
- Mecanica de los Fluidos