# What is Streamline: Definition and 24 Discussions

Streamline is a British Golden Age superhero comic, which appeared in the short-lived magazine Streamline Comics (1947), which only ran for four issues. The character was co-created by Denis Gifford and Bob Monkhouse, and later appeared as a character in the 2000 AD strip Zenith and the independent title Black Tower Comics Group Adventures.

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1. ### Derivation of the Euler equation for a streamline

Hi guys, in the derivation of the Euler equation we apply Newton's 2nd law to a gas flowing through a streamline. To do so, we consider a "box" with sides ##dx## ##dy## and ##dz##: as such; Here, with reference to the image, I can't understand where does that '##+dp##' comes from, and hence...
2. ### A What are the forces acting on an air particle along a fluid streamline curve?

What forces act at air particle at curved streamline, looking from inertial and non-inertial frame of reference? (show free body diagram)
3. ### B Uncovering the Complexities of Streamlined and Steady Flow in Fluid Dynamics

What is the difference between streamlined and steady flow? Is unsteady streamlined flow possible? If yes, could you please explain what are the characteristics of unsteady streamlined flow?
4. ### Deriving Bernoulli's Equation Using Euler's Law of Motion

Hi all, I have attached an image of a page out of the book I am using for context. The blue arrow in Figure 12-3 describes the motion of the particle. I figured the net force would need to be in the same direction, but apparently the net force opposes the motion. So, in Figure 12-3 the pressure...
5. ### Fluid Dynamics -- Find the maximum possible flow speed on the streamline....

Homework Statement At point A in the flow of a compressible fluid, the flow speed is 100 m s−1 and the Mach number of the flow is 0.6. Find (i) the maximum possible flow speed on the streamline through A, and (ii) the flow speed at a point where the pressure has fallen to half its value at...
6. ### Pressure gradient along a streamline using CV analysis

Homework Statement Use a CV analysis to show that an element of fluid along a streamline gives $\partial p/\partial x=-\rho u\partial u/\partial x$ Homework Equations $\sum F=\oint_{CS}^{ } \rho \overrightarrow{V}(\overrightarrow{V_{rel}}\cdot \overrightarrow{n})$ The Attempt at a...
7. M

### How to show Bernoulli's equation applies on same streamline?

When deriving Bernoulli's equation from Navier Stokes, how do we know it is only valid along a streamline? At the very end of my derivation, assuming Newtonian, incompressible, inviscid, irrotational flow I have ##\nabla(\partial_t \phi + |\vec{u}|^2/2+p/\rho + g z) = \vec{0} \implies \partial_t...
8. ### How Does Angular Speed Relate to Velocity in Concentric Circle Streamlines?

Homework Statement The streamlines of a certain flow are concentric circles about the origin, and the absoute value of the velocity varies according to the law |V|=k*r^(n) Show that the angular speed of any fluid element in flow is described by: εz=(1/2)*k*(n+1)*r^(n-1) Homework Equations...
9. ### Stokes Number for Particle Motion?

Hello, I have a question... With the Stokes Number you can derive if particles follow a streamline or not, right? Let's say I am in a windtunnel, the wind is coming from the east. And I have a tube in the wind tunnel (horizontally located) which is 180° opposite to the flow (the opening of the...
10. ### Pathline and Streamline problem

1. Homework Statement As above Homework Equations Not sure. The Attempt at a Solution I've only ever seen one of these problems and it was in the form of V=Axi-Ayj, so much simpler and even then it was poorly explained by the lecturer. I understand what a velocity field is but not much more.
11. ### Determing the equation of a streamline

Homework Statement A fluid has velocity components of u=[30/(2x+1)]m/s and v=(2ty)m/s,where x and y are in meters and t is in seconds. Determine the equation of the streamline that passes through point (2 m, 6 m) at time t = 2 s. Write the equation in the form y={y(x)}m, where x is in meters...
12. ### Plunging into water feet first, as streamlined as you can be

There is a thread on plunging into water but it doesn't specify how you land. Consider that a man plunges into the water vertically with his toes pointing downwards, streamlining his body to the maximum possible extent. How can you calculate if the person falling will die or not? Rather how can...
13. ### Do I understand streamline, streakline and pathlines correctly?

Pathline: When you can see a particle with your eyes and the trajectory of the particle. Streakline: When the particle is "invisible" (such as air) and you have to add paint or dye or something similar in order to see its trajectory. Timeline: When a particle has a pathline, except the...
14. ### Calculating Acceleration Along Streamline XY=4: Problems at Point B?

Along a streamline xy = 4, given u = 2x, v = -2y, I was trying to calculate the acceleration at three different points A(1,4), B(2,2), C(4,1), In my lecture notes, it is said that at A, the fluid is decelerating, at B, the acceleration is zero, and at C it is accelerating. However, i got some...
15. ### Curvature of along a streamline

Hey Guys/Girls and thanks in advance Not quite sure this is in the correct forum since its not a homework question, more private study and curiosity lolz! Im trying to evaluate the curvature along the streamline within a hydrodynamic potential field (fluid flow). I have no issue calculating...
16. ### Velocity profile and streamline equations, help please?

So far I know that dy/dx = V/U is the velocity profile. From what I've read if you know V & U and put it into that equation and the integrate it you get the equation of a streamline. is this correct? An example I have is of a velocity field defined by |U| = (B+Ay^2)e_1. The graph of the...
17. ### Density constant along streamline of incompressible fluid

Question: Show that for a steady flow with div.u=0, the density is constant along streamlines. I just don't see how to approach this question without Bernoulli's equation, I can see that the Lagrangian derivative of the density is zero but that doesn't specifically show that the density is...
18. ### Fluid Streamline Vector Problem

I have a question regarding fluid streamline vector, why is it different from the usual position vector when you take the partial derivative of it in order to obtain the grad of it? For position vector you take partial derivative and obtain the vector along (for say) a curve. But in fluid...
19. ### What Is a Stream-Tube in Fluid Dynamics?

Homework Statement q1. a)Explain the terms stream-tube. b)State the equation of continutity along a stream-tube for an incomperssible fluid. c)A hosepipe with an internal cross sectional area A1 has at its end a nozzle with a hole whose cross-sectional area is A2 (A2<A1). If the...
20. ### Fluid Flows - Complex potential function and general equation of a streamline

Hi All I'm having some problem with this question and was hoping that someone could help me with it. I think I have the first two bits but the rest I'm totally stuck For part (ii) I have the complex potential function as (3x^2)/2 - (3y^2)/2 +6y and the stream function as x(3y-6). Is this...
21. ### Streamline and free surface profile

In a linear shear flow with the free surface being a solitary wave, shall this free surface solitary wave profile coincides with a streamline representing the flow? I have plotted out the streamline of the flow. The streamlines look like the profile of a solitary wave. However the streamline...
22. ### Streamline pattern of a solitary wave?

Hi all! How shall a streamline pattern of a solitary wave look like? I can hardly find people plotting and discussing this, how this is the case? It shall be reasonable to ask for the streamline pattern of a solitary wave, isn't it? If I want to plot the velocity field of the solitary wave...
23. ### Determining Flow Type: Turbulent or Laminar?

Hey guys how do you know when will a flow be turbulent or laminar?i came across a question asking what's the flow of the wind on the sail of a sailboat.i thought that since there is the sail to block the wind when the boat is surfing against the wind, the flow will be turbulent but the ans is...
24. ### Lift as a consequence of streamline arguments

A recently closed thread dealt with the generation of aerodynamic lift, in particular tied to a severe and justified criticism of the "equal transit time"-principle, which often is also called the "Bernoulli effect". However, from what I read, no one showed how streamline arguments can...