Fluid dynamic Definition and 93 Threads

Hi, This is my first post on the PhysicsFormus I am trying to design an inlet and outlet for an axial fan and calculate velocity and pressure profiles in the duct. See the sketch attached. The ultimate goal is to carry out a CFD study but I was wondering if there is an analytical solution for...

Homework Statement How to find the velocity of the air flow around the aerofoil? Homework Equations U - freesteam velocity β - angle of wing camber The Attempt at a Solution To find the velocity of the air flow at each section of the aerofoil, am I right to say that the horizontal velocity...

Hi, I'm trying to do some stress analysis on a tank filled with water, I have split the walls into sections and applied the appropriate pressures. However, I'm confused as to whether I apply the weight of the water+pressure at that height difference to the bottom of the plate; or will the...

Suppose you have a glass of water, and you beat a spoon on the bottom layer of glass through the mouth of glass, repeated beatings in a regular fashion will cause in increased frequency of sound produced due to the spoon beating?What causes such increase in frequency?

Homework Statement The points of interest are at point A and B, I want to calculate the pressures at that point. I am working in gage pressure so we can ignore atmospheric pressure. Homework Equations P = pgh P = sg x specific weight of water x height The Attempt at a Solution Attempting a...

My book states that when a flow around object is considered, Non dimensional momentum flux is defined as the drag coefficient In case of flow through tubes it states The non dimensional momentum flux is defined as the friction factor What do these statements mean? What do they practically...

The main aim of my question is to find time taken by gas filled tank while emptying (from full to zero) it into atmosphere? I require a set of equations which might be used in the calculation of such a situation. Known parameters are: 1. Pressure inside the gas tank. 2. Dimension and shape of...

Complete question: Will flow ever reverse or stop if we increase resistance in this pipe scenario? There are 2 comunicating vessels. The highest vessel is coninuosly alimented with new water. Water in excess flows down on the sides. Water will try to reach the same height in both vessels, so...

Hello there, I am going to implement a numerical method to solve how much Mass of a fluid has gone out of an opened bottle. I am going to get h(t) with some sensors but I am not sure if this expression for Mass gone out "M" is correct. The area of the bottle at the up part. A1 The density of the...

Hello, in some exam questions I've looked at it is stated that the pressure distribution is hydrostatic, even though there is fluid motion. (In these cases the velocity has been constant over the section where the pressure is said to be hydrostatic). Is it really possible to assume that the...

I was reading the paper entitled "The Rayleigh—Taylor instability in astrophysical fluids" by Allen & Hughes (1984), and they discuss relativistically hot plasmas in the context of weak magnetic fields which are presumed to have no dynamic influence, so they take a fluid approach. In this paper...

Hi there. Everyone knows about Torricelli's theorem that says about , in a too big container (opened) the speed of the liquid is given by: v=√(2gh) This result is just for containers that have a hole in the side and the fluid goes out perpendicular to the gravity. And also this result is just...

Homework Statement Consider a layer of paint on a vertical wall, with uniform thickness T and a yield stress of Tau_0. (Paint is a Bingham Plastic). a) Derive an expression for the maximum thickness T0 that can be sustained without vertical flow.b) Derive an expression for the velocity profile...

Suppose I have a wave tank partially filled with a shear thickening Newtonian fluid (Oobleck), on top of which sits a layer of water (separated by a thin membrane to prevent mixing) If I propagate a surface wave in the water layer how will it conduct itself at the Newtonian/Non Newtonian Fluid...

I'm designing a valve that uses a ball to seal the valve. When the valve is empty there is no force acting on top of the ball. When water flows in, it will push up on the ball to dislodge it, water will flow into the valve and push the ball up until it seats into the top hole/chamfer which then...

Is mach cone the area of the shock wave or the wave front of the Mach wave? Usually the diagram for mach cone is this, However I still see some author states that the Mach cone is the shock wave. Shouldn't the shock wave be at the intersection(between the circles) and if the Mach cone is about...

Homework Statement If the velocity v of the air in a boundary layer having a dynamic viscosity of 18x10-6 kg/ms is given in terms of the distance y from the surface by v = ay + by2 where a and b are constants, calculate the surface shear stress if at 1.5 mm from the surface the velocity is 75...

Homework Statement I have a syringe filled with water. This syringe is a cylinder with a length of 3 inches (L), diameter of 1.5 inches (D). Attached to the syringe is a constant force spring, which pushes the plunger into the syringe with a force of 2 pounds (F). Ignore the friction between...

At supersonic speed, air become compressible. However why does Mach number decrease when flow area decrease? I understand that pressure will increase because the density will increase when flow area decrease. However shouldn't the Mach number increase in order to conserve mass flow? Unless the...

Hi, i need help in deriving the velocity potential of a moving 2D cylinder (circle) in potential fluid. The cylinder is moving in negative x direction U(t). I can derive the velocity potential of fluid past a cylinder (cylinder is stationary, in which it is the scalar summation of uniform...

Homework Statement Lag time in hydrograph means teh time of center of rainfall to center of hydrograph , according to my book . Homework EquationsThe Attempt at a Solution Since lag time can be understood by the time taken for the water to reach river , contributing to max discharge ... So ...

So I did a project about a year ago and I can't remember one of the things I wrote in this equation. The equation apparently I got it from NASA's website. https://www.grc.nasa.gov/www/k-12/airplane/dragco.html This is my equation CD = FL/ (0.5 * Air viscosity * V^2 * Area) = 0.4These are the...

I have also asked this question in SO and CFD online Assuming that we have a pneumatic cylinder-piston with arbitrary but known surface area A, a known clarence c, and a known length L. What is the best model to describe the total steady state force applied on the piston considering the...

Here is the experience: I put two electrodes inside paraffin oil (separated by at least 3cm), and submitted the electrodes to high voltage. At 20000 V - 30000 V, strong streams can be observed inside the paraffin oil. Since paraffin oil is a good dielectric, I just would like to understand the...

Homework Statement Problem is given in this image, https://gyazo.com/454370ff9549dcd7c53604ebfe5df105 Homework Equations Continuity or conservation of mass equation: \frac{\partial u}{\partial x} + \frac{\partial w}{\partial z} = 0 Where u is the horizontal velocity and w is the vertical...

Please see the below image, it is a closed and well sealed circulated pipe structure, fully filled with water and no air inside. The density of that green object is greater than water (say 1.2 while water is 1). In this situation, will the green object be sunk? Better with some explanations...

Would it be possible to do a experimental setup where I create a dynamic pressure (10-500 Hz) of around 0.1-2 MPa, using a high force piezoelectric pushing on a piston on a Small volume of oil fluid. There is this paper, where the authors create a pressure wave of around 170 KPa using a...

I observed something which I've never seen before. We left the tap open and the water stream was flowing in a particular pattern. When we placed a beaker under the water stream, the pattern disappeared. And the pattern itself was oscillating. Here's the video link. Below the the photos of the...

Imagine that we have a closed plastic bottle filled with water and then we punch a hole with area A in its cap. How can I find the initial velocity the water will he "fired" with if we squeeze the bottle applying stress S? Assume that we know all about the bottle (moduli, change in volume etc...

I am making a small project at home for my solar panels. I have made a similar project when I was in school but I can't remember the equations. I want to attach an air compressor to a tube then install it on top of a solar panel, and pinch a few holes in it to clean the dust that accumulates...

I'm having trouble finding any valves to use for my certain application. What I'm doing is trying to capture water droplets into a sealed container. What I need is some sort of check valve that needs nearly no pressure to let water through, but keep it contained once it has gone through the...

Hi All, Looking for some help (any is greatly appreciated). I've been tasked with the below, and am unable to find a worked example to cross check my work against. If anyone with a greater knowledge than me could have a look at the below and advise if I'm right the right track. Thanks 1...

Good day to all! I have a question : We have a flowing fluid ( liquid ) with known pressure, flow in the pipe ( pump is pumping it). There are some spherical microparticles in the liquid, let's say 10-15 microns. I want to create force to stop them moving! Will the pressure force be in the form...

Homework Statement http://imgur.com/DSBFIeO I want to find the flowrate through this pipe based on the pipe's diameter, height of the pipe and the pressure difference. I tried to use Bernoulli, but since the diameter on either end is the same, the terms cancel out. I guess Bernoulli's equation...

Homework Statement The conical bearing is placed in a lubricating Newtonian fluid having a viscosity μ. Determine the torque T required to rotate the bearing with a constant angular velocity of ω. Assume the velocity profile along the thickness t of the fluid is linear. Homework Equations v=ωr...

I am trying to develop a calculator to approximate the depth of a trolling rig used by fisherman, which is typically a lead weight with a hook (jighead), attached to a single plastic/rubber shad body (http://www.tacklecoveshop.com/images/Product/icon/1734.jpg). The other typical rig is a...

Ok-I'm actually looking to settle an argument on another forum. I have turbocharged my 1979 Volvo 240, and converted to a later style motor. Instead of drilling and tapping the boss in the block for my oil return to the oil pan, I welded a 1/2" NPT bung into my oil pan. The approximate inner...

Hi I am solving some problems in fluid dynamics I came to this problem that I don't understand how to solve it. A piece of granite floats at the interface of mercury and water contained in a beaker (Fig.). If the densities of granite, water and mercury are ρ, ρ1 and ρ2 respectively, the...

Hi everyone. I've been out of college for some time and forgot how to determine the shape of a droplet. I know how to determine the contact angle based on the interracial energies of three mediums, but I'm not sure how to calculate the actual shape of the hanging drop. In my scenario I have a...

When I studied the fluid dynamic , I saw a quite hard equation (typed in attached file) , I don't know how to prove it , maybe there's a somehow relationship between this eq with Gauss's Divergence Theorem ... Can anyone help me ?

Hallo. I am new at forum, could please somebody send me a code for fluid dynamic in 3D written in Scilab, mathematica or Fortran. I will use it to start with learning!b Thaks, JG

Can anyone explain what stroketlet and rotlet physically mean? Also, I find two forms of strokes equation in different literature, one with the partial derivative of velocity w.r.t. time while another did not, so which is the correct one? Or they refers to different scenario? I am very...

I have a physics project and i chose the topic of fluid dynamic (i don't know of it is really fluid dynamic but i think that is close enough). My level is only a high school student for information, in order to avoid any over complicating explenation. The concept is simple: first pour a...