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Fluid Dynamics
The study of the motion of fluids (liquids and gases) and the forces causing this motion, Fluid Dynamics has several subdisciplines, including hydrodynamics and aerodynamics. To ask and answer questions about Fluid dynamics and its subdisciplines, come on in to the Fluid Dynamics category.
621 Questions
Which is heavier gasoline or motor oil?
if the two were in a container, the oil would raise to the top. if that helps any
What is convective heat transfer?
Convection heat transfer is the transfer of heat by the movement of a fluid.
Can somebody help with a question regarding the equation of continuity?
This is not the answer, but here is the question:
Oil is flowing with a speed of 1.12 m/s through a pipeline with a radius of 0.318 m How many gallons of oil (1 gal equals 3.79 10-3 m3) flow in one day?
Answer:
volume flow= sxAxday= 1.12x3.14x.3182x24x3600=30742.26613 m3/day
Gallons = 3042.26613/3.79E-3=8.111415 Million Gallons per day.
What is head in fluid mechanics?
In fluid mechanics, "head" refers to the potential energy per unit weight of fluid due to its elevation above a reference point. It is often used in pump systems to describe the energy that the pump imparts to the fluid to overcome resistance and lift the fluid to a certain height. Head is typically measured in units of length, such as meters or feet.
Why - when salt is added to water - does the freezing point decrease?
In order for water to freeze, the molecules must align themselves in an orderly fashion. When there are impurities, such as salt (but any impurity will do), they prevent the water from reaching this ordered state as easily. This requires the water to be colder before it freezes.
The salt is an impurity which when added to the ice, causes the melting point to be lowered. so if the temperature is 20 degree C, and you add salt to the ice, the melting will be lowered. It will melt faster than the one without the salt.
What tool is used to measure when a liquid becomes a solid?
Eyes and sense of touch,
Ice pick.
A More Technical Perspective:
In a laboratory setting the change of state between a liquid and a solid is marked by a loss of heat energy while the temperature of the material remains the same. This is due to the energy surrendered by the material as its molecules take on a more "energy economic" configuration. As a consequence the devices need would be a thermometer to measure temperature change and a calorimeter to measure the rate of heat loss.
Alternately the freezing point could be determined by plotting temperature change (with a thermometer) with time in a constant temperature bath. The freezing point would be marked by a flat section in the graph as heat was released by crystallization rather than heat lost due to heat capacity.
What causes a boundary layer to develop in fluids?
A boundary layer develops in fluids due to the friction between the fluid and a solid surface. This friction slows down the fluid velocity near the surface, leading to the formation of a boundary layer where the flow transitions from the no-slip condition at the surface to a freer-flowing condition away from it.
What is the definition of critical Temperature of a Refrigerant?
the temperature which occupied to liquefy the gas at its critical pressure and critical volume ,it is represented by Tc.
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Rafaelrz.
The Critical Temperature of a fluid is the maximum temperature at which it's vapor
form can be liquefied by increasing pressure. The pressure required in this case is
the Critical Pressure of the fluid. At the same time the Critical Pressure of a fluid
is the maximum pressure at which you can liquefy a gas by reducing it's temperature.
The Critical Point of a fluid is the state of the fluid at it's critical temperature and
pressure (The Critical State of the fluid), and the specific volume (m3/kg) or molar
volume (m3/kmol) observed, is the Critical Volume (mass or molar).
An interesting fact is that at the Critical State, the liquid phase and vapor phase at
equilibrium show similar properties.
When the diameter of the cylinder increases what happens to the curve of the meniscus?
When the diameter of the cylinder increases, the meniscus curve becomes less pronounced. This is because the larger diameter allows for a greater surface area, reducing the surface tension effects that create the meniscus curve.
Is dimensionally correct equations necessarily be a physical relation?
No, not all dimensionally correct equations represent physical relationships. Dimensional analysis focuses on the units of measurements in an equation to ensure consistency but does not guarantee the physical relevance of the relationship itself. It is possible to have dimensionally correct equations that do not have a meaningful physical interpretation.
What is the lump on the bow of a ship that cuts through the water first?
This is what's called a bulbous bow and it's designed to reduce drag and increases stability, fuel efficiency, range, and speed.
The velocity of a deepwater wave can be calculated using the formula v = L/T, where v is the velocity, L is the wavelength (50 meters), and T is the period (6.5 seconds). Substituting the values gives v = 50 meters / 6.5 seconds ≈ 7.69 m/s.
Does water temperature change after using alka seltzer?
According to the law of conservation of mass, no it doesn't. It doesn't all stay in the glass, though; some of it escapes into the atmosphere as CO2 but if you were to capture that, you'd have all the mass you started with.
What is the difference between adhesion and viscosity?
Friction is a force that opposes motion of any MOVING object but water resistance is the that force opposing any object moving in water.
Water resistance is only present in water, Friction occurs mostly in solid motions on land or on another solid
They are opposing forces. Water resistance can be considered as a type of friction in water
What makes the whistling noise on bombs as they fall?
If you've ever seen a bomb you will notice that there are tail-fins. There are two purposes to these fins.
- To make the bomb fall where it is intended to go. Hitting a target with a bomb is a hard thing to do and a lot of technology goes into making a bomb the right shape to 'fall straight.'
- These tail-fins are also modified to make the screaming sound as they fall; to add a dimension of terror to a bombing raid.
When turning on a hot water tap how much cold water is lost?
That depends upon the length and diameter of the pipe connecting to the hot water tank. Also, the greater the distance, the more hot/cold mixing will occur, resulting in even greater water loss.
Most copper household plumbing pipe is 1/2" in diameter, and hot water pipes may range from 10' to 80', depending on angles and turns in the plumbing. An 80' pipe will hold about 2 gallons of water. This is water that was heated in the water heater, but upon setting in the pipe gave up all, or most, of its heat to its surroundings.
How do you calculate temperature rise of compressed air?
To calculate the temperature rise of compressed air, you can use the formula: T2 = T1 + (P2 - P1) / (Cp * m), where T2 is the final temperature, T1 is the initial temperature, P2 and P1 are the final and initial pressures, Cp is the specific heat capacity of air at constant pressure, and m is the mass of the air. This formula assumes adiabatic compression and neglects heat transfer and work done in compression.
How did the drinking bird from the 1960s work to continue to bob its head into a glass of water?
The classic bobbing or drinking bird toy has amused kids and adults for years. It appears to be perpetual motion (impossible) but is actually a heat engine with a lot of thermodynamics going on. Although the bird is often thought to be a recent invention it was invented in 1945 and patented in 1946. The "toy" was the brainchild of to PHD candidates, Miles V. Sullivan and George H. Shackley. The science is so complex that it has been the basis of several thermodynamics courses.
The classic bird is made from two glass bulbs joined by a glass tube. The tube extends almost to the bottom of the bottom bulb. It is joined to the top bulb but only at the end. The bulb contains some fluid which evaporates and condenses easily at about room temperature. The bird so far is similar in construction to the "love meters" which move fluids from one bulb to the other based on the heat of your hand.
The other parts of the bird are a bird beak or head made of absorbent material, a pivot which lets the bird balance on a stand, and a glass of water for the bird to dip its beak into. The actual operation of the bird is the result of several gas laws, evaporative cooling and, pressure changed due to heat, leverage and showmanship!
What happens is:
- The birds felt (or similar) head is dampened with water and positioned in front of a glass of water located so that the beak will swing down into the water if it moves forward about the pivot.
- The water on the felt evaporates cooling the head, creating a vacuum in the gases (through condensation of the gas there) and subsequently sucking up fluid from the bottom bulb
- This makes the head heavier and it swings down dipping the nose into the water.
- The water absorbs into the beak fabric, warming the fabric and the bulb, which in turn warms the gases in the head.
- The warmed gases expand increasing the top bulb pressure and expelling the fluid back into the bottom bulb
- The head (now lighter as the fluid is gone) raises, the water starts to evaporate cooling the head and restarting the cycle
How do you calculate the flue gas velocity in airpreheater?
To calculate the flue gas velocity in an air preheater, you would need to know the volumetric flow rate of the flue gas passing through the preheater and the cross-sectional area of the preheater. You can then use the formula: Velocity = Volumetric flow rate / Cross-sectional area of preheater. This calculation will give you the velocity at which the flue gas is moving through the air preheater.
What is the name of the thickness property of a fluid that creates boundary layers and shear stress?
The above description relates to viscosity.
Which will dissolve faster rock salt or iodized salt?
Iodized salt will dissolve faster in water than rock salt. This is because iodized salt has smaller particle size compared to rock salt, allowing it to dissolve more quickly due to the increased surface area exposed to the solvent.
What factors affect surface air temperature?
Factors that affect surface air temperature include solar radiation, cloud cover, altitude, latitude, ocean currents, and land cover. These factors can influence how much sunlight is absorbed or reflected, the distribution of heat across different regions, and the movement of air masses.
Is heating liquid honey a change of state?
No. Simply heating honey, while making it less viscus, does not change its state. It remains a liquid. Unless heating is prolonged enough to cause evaporation, the honey will remain a liquid, so no change of state occurs by simply heating.
Why after 24 hours helium balloon won't fly what is happening with the helium?
Helium atoms are very small and able to diffuse through the balloon material over time, leading to a loss of buoyancy. As a result, the balloon becomes deflated and unable to lift the weight of the rubber and any attachments.
Sports where friction is either supporting or opposing these games?
Skiing and snowboarding (Skis rubbing against snow slows them down)
Skateboarding (Rolling friction, it's a matter of opinion if it supports or opposes them)
Swimming (fluid friction makes it harder for them to swim against it)
Those are just a few.
