Questions tagged [fluid-dynamics]
The quantitative study of the motion, behavior, and governing forces of fluids (liquids and gases).
182 questions from the last 365 days
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Kinetic energy of the velocity field generated by a helical Clifford torus vortex in an incompressible fluid
Context: I am studying energy properties of toroidal vortex configurations, motivated by the literature on topological solitons (Skyrmions, Hopfions, and related structures). This is a question about ...
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Validation of approach for fluid problem from SS Krotov's aptitude problems (1.113) [closed]
I was doing problem 1.113 from S.S. Krotov's physics book. I got the correct answer, but my method was very different. I wanted to verify the correctness of this method.
Question:
A jet plane with a ...
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Water waves don't transfer matter but how does a kayak move? I know it's probably simple but I get very confused when it comes to physics
I heard somewhere that it is because you push boat backward which pushes you forward due to the paddle but isn't a back and forth motion a wave too? I'd appreciate it if someone could help.
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Centripetal vs Centrifugal force in centrifugal compressor
I am trying to understand the working principles of a centrifugal compressor. I understand that gas enters the compressor and is then spun around with an impeller. The gas then moves radially outwards ...
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Poisson bracket form of an equation in generalized hydrodynamics
This question talks about generalized hydrodynamics (GHD) (a relatively new field that studies non-equilibrium integrable systems).
In generalized hydrodynamics (GHD), the main EOM is the Euler-...
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How should one interpret the terms in the continuity equation in Eulerian and Lagrangian language?
I am trying to understand the Eulerian and Lagrangian meanings of the continuity equation
$$
\frac{\partial \rho}{\partial t}+(\mathbf v\cdot\nabla)\rho+\rho\,\nabla\cdot\mathbf v=0
\quad\...
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What's the mass balance equation in Lagrangian frame?
I am a class 12th student; a few weeks back, i was revising about continuum mechanics, then i noticed something was off; we have the mass balance equation in Eulerian frame and Lagrangian frame for a ...
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Emergence of macroscale Generalized Hydrodynamics (GHD) from microscale integrable systems: How is this possible?
I am trying to wrap my head around Generalized Hydrodynamics (GHD) (see, for example, the 2024 plenary lecture The equation of generalised hydrodynamics by Prof. Benjamin Doyon [1]) and how it applies ...
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Interpretation of convective flux in Reynolds Transport Theorem
Can someone help me understand the Reynolds Transport Theorem in this form:
$$\frac{d}{dt}\int_{B_t} f(\mathbf{x},t)\,dv
=
\int_{B_t}\frac{\partial f}{\partial t}\,dv
+
\int_{\partial B_t} f \,\left( \...
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Macroscopic viscosity explanation
The image attached is just enlarging the layers of the fluid model that is typically used to explain what viscosity exactly is, I have a few questions here, but first let me write down my ...
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Catamaran moving in reverse with a crosswind
I have been busting my head with this one. I have found one video explaining this and to my understanding the answer is wrong, hence I am seeking help to truly understand physics once and for all.
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Can pouring liquid into long, narrow orifices cause resonnance (whistling)?
When I put oil into the orifice of my car engine (or transmission fluid into my transmission, via a narrow orifice), I hear a whistling sound.
What is the physics/acoustics of pouring liquids into ...
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In two-phase flow with dynamic interface $Σ(t)$, how is the full-cycle work integral evaluated when $[P]_Σ = γκ + f$ is non-zero?
Background
In single-phase incompressible flow, the net work done by the pressure field over a closed streamline is zero, because $\nabla P$ is conservative and:
$$\oint_{\text{cycle}} \int_V -\nabla ...
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Vlasov moment closure: does a $1/r³$ interaction kernel change the scaling of $\hbar_{\text{eff}} $ versus the gravitational $1/r$ case?
Chavanis (2011) showed that a self-gravitating Vlasov gas produces an effective Schrödinger equation in the fluid limit, with $\hbar_{\text{eff}} \sim 2m\sigma\lambda$, where $\sigma$ is velocity ...
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How to model a hose subject to drag and its own weight? [closed]
I want to model a hose with length $L$ and mass $M$ (mass per length $\lambda$), radius $R$ subject to a smooth flow (dynamic pressure $q$). I want to set the drag coefficient of each section of the ...
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