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SST (Menter's shear stress transport) turbulence model [11] is a widely used and robust two-equation eddy-viscosity turbulence model used in computational fluid dynamics. The model combines the k-omega turbulence model and K-epsilon turbulence model such that the k-omega is used in the inner region of the boundary layer and switches to the k ...
In meteorology, clear-air turbulence (CAT) is the turbulent movement of air masses in the absence of any visual clues such as clouds, and is caused when bodies of air moving at widely different speeds meet.
A variety of models exist for gusts [3] but only two, the Dryden and von Kármán models, are generally used for continuous gusts in flight dynamics applications. [2] [4] Both of these models define gusts in terms of power spectral densities for the linear and angular velocity components parameterized by turbulence length scales and intensities.
WHAT IS TURBULENCE? Turbulence or pockets of disturbed air can have many causes, most obviously the unstable weather patterns that trigger storms, according to an industry briefing by planemaker ...
A classical model for the phugoid period can be simplified to about (0.85 times the speed in knots) seconds, but this only really works for larger aircraft. [ further explanation needed ] Phugoids are often demonstrated to student pilots as an example of the speed stability of the aircraft and the importance of proper trimming.
Reynolds stress equation model (RSM), also referred to as second moment closures are the most complete classical turbulence model. In these models, the eddy-viscosity hypothesis is avoided and the individual components of the Reynolds stress tensor are directly computed.
The Dryden model treats the linear and angular velocity components of continuous gusts as spatially varying stochastic processes and specifies each component's power spectral density. The Dryden wind turbulence model is characterized by rational power spectral densities, so exact filters can be designed that take white noise inputs and output ...
Turbulence kinetic energy is then transferred down the turbulence energy cascade, and is dissipated by viscous forces at the Kolmogorov scale. This process of production, transport and dissipation can be expressed as: D k D t + ∇ ⋅ T ′ = P − ε , {\displaystyle {\frac {Dk}{Dt}}+\nabla \cdot T'=P-\varepsilon ,} where: [ 1 ]