The purpose of this glossary is that the new concepts that we are learning throughout the subject are as clear as possible.
Convection heat transfer coefficient
Noun
The convective heat transfer coefficient, h, can be defined as: The rate of heat transfer between a solid surface and a fluid per unit surface area per unit temperature difference.
Example: The convective heat transfer coefficient is dependent upon the physical properties of the fluid and the physical situation. The convective heat transfer coefficient is not a property of the fluid. It is an experimentally determined parameter whose value depends on all the variables influencing convection such as the surface geometry, the nature of fluid motion, the properties of the fluid, and the bulk fluid velocity.
en: Coeficiente de transferencia de calor por convección
Critical Reynold’s number
Noun
The Reynolds number is the ratio of inertial forces to viscous forces and is a convenient parameter for predicting if a flow condition will be laminar or turbulent.
Example: The critical Reynolds number is associated with the laminar-turbulent transition, in which a laminar flow becomes turbulent. This is an extraordinarily complicated process, which at present is not fully understood.
en: Número crítico de Reynolds
Friction Coefficient
Noun
Coefficient of friction is a measure of the amount of friction existing between two surfaces. When you find a coefficient of friction, you’re calculating the resistance to motion at the interface of two surfaces of similar or dissimilar materials.
Example: The power of this friction force depends on the materials that are pressing against one another. For instance, a steel bar will slide much more easily on a sheet of ice than on a slab of concrete. In these examples, the steel-on-ice combination has a much lower coefficient of friction.
en: Coeficiente de fricción
Kinematic viscosity
Noun
Kinematic viscosity is dynamic viscosity divided by density (Formula F7.9) and is the ratio of viscous forces to inertia forces.
Example: La viscosidad cinemática de los lubricantes, es decir, el cociente entre la viscosidad dinámica y la densidad del aceite, es función de la temperatura y es un factor importante que determina el nivel de ruido generado por las transmisiones. Los perfiles de viscosidad de los lubricantes investigados se determinaron utilizando el método Ubbelohde DIN 51562
en: Viscosidad cinemática
Laminar flow
Noun
uninterrupted flow in a fluid near a solid boundary in which the direction of flow at every point remains constant
Example: The laminar flow of the wind seems to be optimum, too, which should make calculations easier for Bryson DeChambeau.
en: Flujo laminar
Nusselt number
Noun
The Nusselt number is defined as the ratio of convection heat transfer to fluid conduction heat transfer under the same conditions.
Example: Nusselt number is an important parameter that can contribute to a better rate of heat exchange. It is basically a function of Reynolds and Prandtl number.
en: Número de Nusselt
Prandtl number
Noun
The Prandtl number is defined as the ratio of momentum diffusivity to thermal diffusivity. Thermal Engineering
Example: The momentum diffusivity, or as it is normally called, kinematic viscosity, tells us the material’s resistance to shear-flows (different layers of the flow travel with different velocities due to e.g. different speeds of adjacent walls) in relation to density.
en: Número de prandtl
Reynold number
Noun
The Reynolds number is a dimensionless number used to categorize the fluids systems in which the effect of viscosity is important in controlling the velocities or the flow pattern of a fluid. Mathematically, the Reynolds number.
Example: The Reynolds number is used to determine whether a fluid is in laminar or turbulent flow. Based on the API 13D recommendations, it is assumed that a Reynolds number less than or equal to 2100 indicates laminar flow, and a Reynolds number greater than 2100 indicates turbulent flow.
en: Número de Reynold
Shear stress
Noun
A shear stress, denoted, is defined as the stress component coplanar with a cross section of material. The shear stress arises from the component of the force vector parallel to the cross section.
Example: To understand it, let's see in the following example an analogy that will simplify our concept, in panel A we have a book that is at rest on a table, then in panel B we see how with our hand we exert a tangential tension (shear stress) on the top cover of the book, which will generate deformation (strain):
en: Esfuerzo cortante
Turbulent flow
Turbulent flow is a type of fluid (gas or liquid) flow in which the fluid undergoes irregular fluctuations, or mixing, in contrast to laminar flow, in which the fluid moves in smooth paths or layers.
Example: In turbulent flow the speed of the fluid at a point is continuously undergoing changes in both magnitude and direction. The flow of wind and rivers is generally turbulent in this sense, even if the currents are gentle. The air or water swirls and eddies while its overall bulk moves along a specific direction.
