1,721,157 research outputs found
A New Application of the Reciprocity Relations to the Study of Fluid Flow through Fixed Beds
No full textCreeping flow through an array of spheres with small volume fraction c is studied theoretically. It is observed that it can be described macroscopically by Brinkman’s equation. A generalized version of the reciprocity relations is used to determine the viscous term up to O(c^2) for the case of random configuration and up to O(c^3) for the case of periodic, cubic configurations of the fixed bed
Fenomeni di Trasporto (II edizione)
No full textQuesto libro di testo trae origine dalla necessità di fornire agli studenti dei corsi di laurea triennali e di laurea specialistica in Ingegneria Chimica, Meccanica. Biomedica e Nucleare le basi della meccanica dei fluidi e del trasporto di calore e di massa. L'idea fondante di questa disciplina è quella di unificare l' approccio fisico e matematico al trasporto di quantità di moto, energia e massa, descrivendoli nei termini di flussi convettivi e flussi diffusivi. Questi ultimi, a loro volta, sono legati alla forza motrice che li determina, cioè ai gradienti di velocità, energia interna e potenziale chimico, attraverso delle "diffusività" che misurano la resistenza del sistema, cioè la sua riluttanza ad abbandonare I equilibrio termodinamico, dove i gradienti suddetti sono nulli. Queste resistenze sono responsabili del carattere irreversibile del trasporto di quantità di moto, calore e massa e prendono il nome di viscosità, conducibilità termica e diffusività massica, rispettivamente
Transport phenomena in multiphase flows
No full textThis textbook provides a thorough presentation of the phenomena related to the transport of mass, momentum and energy. It lays all the basic physical principles, then for the more advanced readers, it offers an in-depth treatment with advanced mathematical derivations and ends with some useful applications of the models and equations in specific settings. The important idea behind the book is to unify all types of transport phenomena, describing them within a common framework in terms of cause and effect, respectively represented by the driving force and the flux of the transported quantity. The approach and presentation are original in that the book starts with a general description of transport processes, providing the macroscopic balance relations of fluid dynamics and heat and mass transfer, before diving into the mathematical realm of continuum mechanics to derive the microscopic governing equations at the microscopic level. The book is a modular teaching tool and can be used either for an introductory or for an advanced graduate course. The last 6 chapters will be of interest to more advanced researchers who might be interested in particular applications in physics, mechanical engineering or biomedical engineering. All chapters are complemented with exercises that are essential to complete the learning process
Muspell: un Codice Numerico per il Dimensionamento di Scambiatori di Calore del Tipo Shell-and-Tube.
No full text
A Non-local Phase Field Model of Bohm’s Quantum Potential
No full textAssuming that the free energy of a gas depends non-locally on the logarithm of its mass density, the body force in the resulting equation of motion consists of the sum of density gradient terms. Truncating this series after the second term, Bohm’s quantum potential and the Madelung equation are identically obtained, showing explicitly that some of the hypotheses that led to the formulation of quantum mechanics admit a classical interpretation based on non-locality
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