Turbulence in human fluid dynamics
In laminar flow, fluid is moving faster in the center and more slowly at the edges of the pipe. A critical speed is reached, since obstacles must be met along the way, as 'friction' builds up and the path narrows, when dynamic pressure(flow) falls, just downstream of the obstacle and central fluid flow slows. There is less ordered movement and separation of fluid into 'particulates'(drops), caused by 'friction' or traction and these particulates bombard the walls of the pipe. The dynamic pressure downstream of the obstacle falls as that at the edges rises(from impact and directional change in droplets), which normally is at low pressure in tne laminar flow; this due to redistribution from the center to the sides. Pressure on the walls of the pipe increases because of this redistribution and the separation of the fluid into droplets, which hit the walls with greater impact, creating strong vibrations. Collision of downstream flow with upstream flow created by directionalchange on impact willlead to stasis and more static pressure. The overall flow slows down because of traction.
Essentially, as sound, from the turbulent fluid streams hitting the walls and setting them to vibrate at the natural frequency of the vessel, comes in phase with each other, the impacts reinforce, leading to resonance, akin to resonance obtained when a tuning fork is struck and it sets another fork into amplified air vibrations equal to its natural frequency or air is blown into a flute or over an open pipe, the anti-node at the open end(s)with maximum vibrations set a stationary sound signal.
. The area just downstream of the obstacle may be at significantly low pressure, while the ones immediately next to it, towards the wall, are at a higher pressure and this will lead to the formation of small fluid currents called eddies(movement from high to low pressure). Due to fluid eddies, there is much slowing of flow downstream, and the overall speed falls even more.
So, increasing velocity(dynamic pressure) will eventually give rise to turbulence in viscous fluid(traction-prone), high wall pressure(pressure against the walls of the artery) and will slow down the flow downstream. There is limit to what pumping pressure can do to increase flow of fluid, because of turbulence.
The heart pumps blood round the body and the force of contraction determines the dynamic pressure produced and the velocity of flow. Blood pressure, generated from contraction of the heart muscle fibers will create turbulence, evident as sound when a major artery is obstructed as the arm is cuffed to take the B.P. with the stethoscope.
Physical conditions which lead to high blood pressure include the narrowing of the blood vessels( e.g in atherosclerosis and stress), which leads to blood build-up in the heart and stretching of the heart muscle. The heart responds by generating more contraction force as it recoils. The speed builds up further, and with it, turbulence and even higher arterial blood pressure. This severely limits perfusion, which pumping(dynamic) pressure seeks to achieve, in the first place, following the narrowing of blood vessels. The vicious cycle continues and the heart grows in size and will eventually get damaged and fail from stretch(dilated cardiomyotrophy)) or contraction(hypertrophic cardiomyotrophy with scar tissue) and pump less blood. This is why high blood pressure must be controlled by dilating the blood vessels to increase flow and by reducing the heart pumping work (effort). Reducing the dynamic pressure by creating too open blood vessels will, however, severely limit the velocity of flow from the heart and should be guarded against. Turbulence is also detected when major arteries are blocked by an obstruction. Pulsation may be a visible or palpable sign. Increase in blood cells will also increase blood viscosity, 'particulate' impact and vibration and this will lead to turbulent flow and increased blood pressure.
When we rapidly inhale air into our lungs, during breathing, we create turbulent pressure resonance( flapping sound) on floppy structures(uvala), and bellowing resonance( musical note) from air passing in obstructed(narrowed) pipe structures, setting a stationary sound wave(reflected sound wave either at the node or antinode and with the antinode at the open end of the tube) because relatively less force is required to create the required frequency of vibration for sound to form. Such obstruction is provided by the tongue, uvula, epiglottis, hair, water particles/mucus that line our airway or contraction that offers resistance to the lungs on emptying, creating swipes leading to sniffing sound, or flap and beat the tube to produce flapping sound or set a stationary wave and produce wheezing. Farting is air turbulence at obstructed anal opening and if fast enough will create sound through a staionary wave which requires less energy humanly and unaidedly possible because of sound reflection through turbulence at the edges of the tube that amplifies sound as the antinode at the open end. When we speak, we create air turbulence in the vocal cord with the wind pipe acting as an 'obstructed' pipe full of air which vibrates at the frequency with enough energy set up to match the pipe size and produce sound. Snoring is turbulence, produced over the epiglottis, uvula and other obstructions, which vibrate and resonate, giving the characteristic flapping snoring sound in addition to wheezing sound formed in the 'copllapsed'(narrowed) vocal cord from unconsciousness. Since flow may be severely limited by obstruction and eddies, this can lead to sleep apnea. When we whistle, we create turbulence, through the lips and set a stationary sound wave over them, with air at the opening vibrating maximally, at sound frequency produced by energy commensurate with the column size. The series of turbulent obstructions, and releases by easing off on the pressure, produces the characteristic sound.
Dr Oliver Verbe Birnso
Essentially, as sound, from the turbulent fluid streams hitting the walls and setting them to vibrate at the natural frequency of the vessel, comes in phase with each other, the impacts reinforce, leading to resonance, akin to resonance obtained when a tuning fork is struck and it sets another fork into amplified air vibrations equal to its natural frequency or air is blown into a flute or over an open pipe, the anti-node at the open end(s)with maximum vibrations set a stationary sound signal.
. The area just downstream of the obstacle may be at significantly low pressure, while the ones immediately next to it, towards the wall, are at a higher pressure and this will lead to the formation of small fluid currents called eddies(movement from high to low pressure). Due to fluid eddies, there is much slowing of flow downstream, and the overall speed falls even more.
So, increasing velocity(dynamic pressure) will eventually give rise to turbulence in viscous fluid(traction-prone), high wall pressure(pressure against the walls of the artery) and will slow down the flow downstream. There is limit to what pumping pressure can do to increase flow of fluid, because of turbulence.
The heart pumps blood round the body and the force of contraction determines the dynamic pressure produced and the velocity of flow. Blood pressure, generated from contraction of the heart muscle fibers will create turbulence, evident as sound when a major artery is obstructed as the arm is cuffed to take the B.P. with the stethoscope.
Physical conditions which lead to high blood pressure include the narrowing of the blood vessels( e.g in atherosclerosis and stress), which leads to blood build-up in the heart and stretching of the heart muscle. The heart responds by generating more contraction force as it recoils. The speed builds up further, and with it, turbulence and even higher arterial blood pressure. This severely limits perfusion, which pumping(dynamic) pressure seeks to achieve, in the first place, following the narrowing of blood vessels. The vicious cycle continues and the heart grows in size and will eventually get damaged and fail from stretch(dilated cardiomyotrophy)) or contraction(hypertrophic cardiomyotrophy with scar tissue) and pump less blood. This is why high blood pressure must be controlled by dilating the blood vessels to increase flow and by reducing the heart pumping work (effort). Reducing the dynamic pressure by creating too open blood vessels will, however, severely limit the velocity of flow from the heart and should be guarded against. Turbulence is also detected when major arteries are blocked by an obstruction. Pulsation may be a visible or palpable sign. Increase in blood cells will also increase blood viscosity, 'particulate' impact and vibration and this will lead to turbulent flow and increased blood pressure.
When we rapidly inhale air into our lungs, during breathing, we create turbulent pressure resonance( flapping sound) on floppy structures(uvala), and bellowing resonance( musical note) from air passing in obstructed(narrowed) pipe structures, setting a stationary sound wave(reflected sound wave either at the node or antinode and with the antinode at the open end of the tube) because relatively less force is required to create the required frequency of vibration for sound to form. Such obstruction is provided by the tongue, uvula, epiglottis, hair, water particles/mucus that line our airway or contraction that offers resistance to the lungs on emptying, creating swipes leading to sniffing sound, or flap and beat the tube to produce flapping sound or set a stationary wave and produce wheezing. Farting is air turbulence at obstructed anal opening and if fast enough will create sound through a staionary wave which requires less energy humanly and unaidedly possible because of sound reflection through turbulence at the edges of the tube that amplifies sound as the antinode at the open end. When we speak, we create air turbulence in the vocal cord with the wind pipe acting as an 'obstructed' pipe full of air which vibrates at the frequency with enough energy set up to match the pipe size and produce sound. Snoring is turbulence, produced over the epiglottis, uvula and other obstructions, which vibrate and resonate, giving the characteristic flapping snoring sound in addition to wheezing sound formed in the 'copllapsed'(narrowed) vocal cord from unconsciousness. Since flow may be severely limited by obstruction and eddies, this can lead to sleep apnea. When we whistle, we create turbulence, through the lips and set a stationary sound wave over them, with air at the opening vibrating maximally, at sound frequency produced by energy commensurate with the column size. The series of turbulent obstructions, and releases by easing off on the pressure, produces the characteristic sound.
Dr Oliver Verbe Birnso
Comments
Post a Comment