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Vortex-induced vibration (VIV) is an important source of fatigue damage of offshore oil exploration drilling, export, production risers, including steel catenary risers (SCRs) and tension leg platform (TLP) tendons or tethers. These slender structures experience both current flow and top-end vessel motions, which both give rise to the flow ...
The Scruton number (Sc) is an important parameter for vortex-induced vibration (excitation) of structures, vibrations caused by rain or wind, dry inclined cable galloping, and wake galloping, the unstable airflow that forms around bridge cables and other cylindrically-structured buildings. [1]
The frequency at which vortex shedding takes place for a cylinder is related to the Strouhal number by the following equation: = Where is the dimensionless Strouhal number, is the vortex shedding frequency (Hz), is the diameter of the cylinder (m), and is the flow velocity (m/s).
Animation of vortex street created by a cylindrical object; the flow on opposite sides of the object is given different colors, showing that the vortices are shed from alternating sides of the object A look at the Kármán vortex street effect from ground level, as air flows quickly from the Pacific Ocean eastward over Mojave Desert mountains.
The vorticity equation of fluid dynamics describes the evolution of the vorticity ω of a particle of a fluid as it moves with its flow; that is, the local rotation of the fluid (in terms of vector calculus this is the curl of the flow velocity). The governing equation is:
where p describes the magnetisation direction in the origin (p=1 (−1) for (=) = ()) and W is the winding number. Considering the same uniform magnetisation, i.e. the same p value, the winding number allows to define the skyrmion (()) with a positive winding number and the antiskyrmion (()) with a negative winding number and thus a topological charge opposite to the one of the skyrmion.
Exact solutions to classical nonlinear magnetic equations include the Landau–Lifshitz equation, the continuum Heisenberg model, the Ishimori equation, and the nonlinear Schrödinger equation. Vortex rings are torus-shaped vortices where the axis of rotation is a continuous closed curve. Smoke rings and bubble rings are two well-known examples.
Continuous charge distribution. The volume charge density ρ is the amount of charge per unit volume (cube), surface charge density σ is amount per unit surface area (circle) with outward unit normal nĚ‚, d is the dipole moment between two point charges, the volume density of these is the polarization density P.