What is stratified flow pattern?
Stratified flow is a basic flow pattern for gas-liquid and liquid-liquid two-phase flows in a gravitational field, where the lighter fluid flows above the heavier one. This flow pattern is frequently encountered in various important industrial processes.
What is stratified flow in fluid mechanics?
Abstract. The name, stratified flow, is applied to a flow primarily in the horizontal direction that is affected by a vertical variation of the density. Such flows are of considerable importance in geophysical fluid mechanics.
What is the definition of flow in physics?
Introduction. Flow is defined as the quantity of fluid (gas, liquid or vapour) that passes a point per. unit time. A simple equation to represent this is. Flow (F) = Quantity (Q)
What does stably stratified mean?
A stably stratified fluid is one in which the fluid density increases with depth. A characteristic of a stably stratified fluid is the ability to support and propagate wave motions.
What is annular flow?
1. n. [Production Logging] A multiphase flow regime in which the lighter fluid flows in the center of the pipe, and the heavier fluid is contained in a thin film on the pipe wall. The lighter fluid may be a mist or an emulsion.
What causes slug flow?
What is Slug Flow in Piping? Slug Flow is a typical two-phase flow where a wave is picked up periodically by the rapidly moving gas to form a frothy slug, which passes along the pipe at a greater velocity than the average liquid velocity.
What is a stratified gas?
Stratification is the extent to which the heavier gases tend to settle to the bottom and the lighter gases rise to the top of an initially uniform air mixture, in the absence of bulk air movement. In well ventilated areas, gas stratification is irrelevant.
Why does stratified flow has horizontal gas liquid interface?
Stratified smooth flow pattern is characterized by the smooth flat undisturbed interface separating the gas and liquid phases due to the significant difference in density. This pattern occurs when the superficial gas and liquid velocities are low enough and not sufficient to cause waves.
What is meant by turbulent flow?
turbulent flow, 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. In turbulent flow the speed of the fluid at a point is continuously undergoing changes in both magnitude and direction.
What is steady flow?
Definition of steady flow : a flow in which the velocity of the fluid at a particular fixed point does not change with time. — called also stationary flow. — compare uniform flow.
What is atmosphere stratification?
The atmosphere is divided into an inner and an outer atmosphere; from the latter particles may escape. The inner atmosphere is divided into three spheres—troposphere, stratosphere, and ionosphere—with each sphere in turn being subdivided into 3 or 4 layers.
What is mist flow?
Mist flow is a flow regime of two-phase gas-liquid flow. It occurs at very high flow rates and very high flow quality. This condition causes the liquid film flowing on the channel wall to be thinned by the shear of the gas core on the interface until it becomes unstable and is destroyed.
What are the characteristics of stratified flows?
Stratified flows are very common in the nature, for example in the ocean and in the atmosphere. In the internal flows the stratified flow occurs at low liquid and gas velocities. As the velocity of the gas increases, the horizontal interface becomes more disturbed and waves may be formed.
What is a stratified fluid system?
A stratified fluid may be defined as the fluid with density variations in the vertical direction. For example, air and water; both are fluids and if we consider them together then they can be seen as a stratified fluid system. Density variations in the atmosphere profoundly affect the motion of water and air.
What determines the pressure drop and liquid hold-up in stratified flow?
In stratified flow, the determination of pressure drop and liquid hold-up requires an accurate prediction of the friction at the wall and at the interface. Indeed, for fully developed flow, the pressure drop is controlled by the friction at the wall of each phase and by the weight of the liquid, which is related to the hold-up.
Does height affect the stability of a stratified fluid?
If however the fluid tends to be stable if density decreases with height. It is known that the sub critical flow of a stratified fluid past a barrier produce motions upstream of the barrier.