Open Access. Powered by Scholars. Published by Universities.^{®}
Physical Sciences and Mathematics Commons^{™}
Open Access. Powered by Scholars. Published by Universities.^{®}
 Keyword

 Hydrodynamics (2)
 Turbulence (2)
 Stokes wave (2)
 Airsea interactions (2)
 Asymptotic solution (1)

 Asymmetric flow (1)
 Atmospheric modeling (1)
 Energy transfers (1)
 Cavitation (1)
 Energytransfer rate (1)
 Breaking waves (1)
 Finite volume (1)
 Critical layer (1)
 Atmospheric oceanic interactions (1)
 3D water waves (1)
 Elliptic functions (1)
 Deepwater waves (1)
 Eulerian (1)
 Growth factors (1)
 Dyad theory (1)
 Critical height (1)
 Convection (1)
 EmdenFowler (1)
 Coherent structures (1)
 Cat's eye structures (1)
 Electrodynamics (1)
 Airsea interface (1)
 Appell invariant (1)
 Airsea interaction (1)
 Abel (1)
Articles 1  14 of 14
FullText Articles in Physical Sciences and Mathematics
An Asymptotic Analysis For Generation Of Unsteady Surface Waves On Deep Water By Turbulence, Shahrdad Sajjadi
An Asymptotic Analysis For Generation Of Unsteady Surface Waves On Deep Water By Turbulence, Shahrdad Sajjadi
Publications
The detailed mathematical study of the recent paper by Sajjadi, Hunt and Drullion (2014) is presented. The mathematical developement considered by them, for unsteady growing monochromatic waves is also extended to Stokes waves. The present contribution also demonstrates agreement with the pioneering work of Belcher and Hunt (1993) which is valid in the limit of the complex part of the wave phase speed c_{i }↓ 0. It is further shown that the energytransfer parameter and the surface shear stress for a Stokes wave reverts to a monochromatic wave when the second harmonic is excluded. Furthermore, the present theory can be ...
Wave Motion Induced By Turbulent Shear Flows Over Growing Stokes Waves, Shahrdad Sajjadi, Serena Robertson, Rebecca Harvey, Mary Brown
Wave Motion Induced By Turbulent Shear Flows Over Growing Stokes Waves, Shahrdad Sajjadi, Serena Robertson, Rebecca Harvey, Mary Brown
Publications
The recent analytical of multilayer analyses proposed by Sajjadi et al. (J Eng Math 84:73, 2014) (SHD14 therein) is solved numerically for atmospheric turbulent shear flows blowing over growing (or unsteady) Stokes (bimodal) water waves, of lowtomoderate steepness. For unsteady surface waves, the amplitude a(t)∝ekcita(t)∝ekcit, where kcikci is the wave growth factor, k is the wavenumber, and cici is the complex part of the wave phase speed, and thus, the waves begin to grow as more energy is transferred to them by the wind. This will then display the critical height to a point, where ...
Growth Of Groups Of Wind Generated Waves, Frederique Drullion, Shahrdad Sajjadi
Growth Of Groups Of Wind Generated Waves, Frederique Drullion, Shahrdad Sajjadi
Publications
In this paper we demonstrate numerical computations of turbulent wind blowing over group of waves that are growing in time. The numerical model adopted for the turbulence model is based on differential secondmoment model that was adopted for growing idealized waves by Drullion & Sajjadi (2014). The results obtained here demonstrate the formation of cat'seye which appear asymmetrically over the waves within a group.
Growth Of Unsteady Wave Groups By Shear Flows, Shahrdad Sajjadi, Julian Hunt, Frederique Drullion
Growth Of Unsteady Wave Groups By Shear Flows, Shahrdad Sajjadi, Julian Hunt, Frederique Drullion
Publications
A weakly nonlinear theory has been proposed and developed for calculating the energy transfer rate to individual waves in a group. It is shown what portion of total energy transfer rate, over the envelope of wave group, affects individual waves in the group. From this an expression for complex phase speed of individual waves is calculated. It is deduced that each wave in a group does not grow at the same rate. It is shown that the critical layer is no longer symmetrical compared with the ideal monochromatic waves. This asymmetry causes the critical layer height to be lower over ...
Growth Of Stokes Waves Induced By Wind On A Viscous Liquid Of Infinite Depth, Shahrdad Sajjadi
Growth Of Stokes Waves Induced By Wind On A Viscous Liquid Of Infinite Depth, Shahrdad Sajjadi
Publications
The original investigation of Lamb (1932, x349) for the effect of viscosity on monochromatic surface waves is extended to account for secondorder Stokes surface waves on deep water in the presence of surface tension. This extension is used to evaluate interfacial impedance for Stokes waves under the assumption that the waves are growing and hence the surface waves are unsteady. Thus, the previous investigation of Sajjadi et al. (2014) is further explored in that (i) the surface wave is unsteady and nonlinear, and (ii) the effect of the water viscosity, which affects surface stresses, is taken into account. The determination ...
Evolution Of Spherical Cavitation Bubbles: Parametric And ClosedForm Solutions, Stefan C. Mancas, Haret C. Rosu
Evolution Of Spherical Cavitation Bubbles: Parametric And ClosedForm Solutions, Stefan C. Mancas, Haret C. Rosu
Publications
We present an analysis of the RayleighPlesset equation for a three dimensional vacuous bubble in water. In the simplest case when the effects of surface tension are neglected, the known parametric solutions for the radius and time evolution of the bubble in terms of a hypergeometric function are briefly reviewed. By including the surface tension, we show the connection between the RayleighPlesset equation and Abel’s equation, and obtain the parametric rational Weierstrass periodic solutions following the Abel route. In the same Abel approach, we also provide a discussion of the nonintegrable case of nonzero viscosity for which we perform ...
Formation Of ThreeDimensional Surface Waves On DeepWater Using Elliptic Solutions Of Nonlinear Schrödinger Equation, Shahrdad G. Sajjadi, Stefan C. Mancas, Frederique Drullion
Formation Of ThreeDimensional Surface Waves On DeepWater Using Elliptic Solutions Of Nonlinear Schrödinger Equation, Shahrdad G. Sajjadi, Stefan C. Mancas, Frederique Drullion
Publications
A review of threedimensional waves on deepwater is presented. Three forms of threedimensionality, namely oblique, forced and spontaneous types, are identified. An alternative formulation for these threedimensional waves is given through cubic nonlinear Schrödinger equation. The periodic solutions of the cubic nonlinear Schrödinger equation are found using Weierstrass elliptic ℘ functions. It is shown that the classification of solutions depends on the boundary conditions, wavenumber and frequency. For certain parameters, Weierstrass ℘ functions are reduced to periodic, hyperbolic or Jacobi elliptic functions. It is demonstrated that some of these solutions do not have any physical significance. An analytical solution of cubic nonlinear ...
Asymptotic MultiLayer Analysis Of Wind Over Unsteady Monochromatic Surface Waves, Shahrdad Sajjadi, Julian Hunt, Frederique Drullion
Asymptotic MultiLayer Analysis Of Wind Over Unsteady Monochromatic Surface Waves, Shahrdad Sajjadi, Julian Hunt, Frederique Drullion
Publications
Asymptotic multilayer analyses and computation of solutions for turbulent flows over steady and unsteady monochromatic surface wave are reviewed, in the limits of low turbulent stresses and small wave amplitude. The structure of the flow is defined in terms of asymptoticallymatched thinlayers, namely the surface layer and a critical layer, whether it is ‘elevated’ or ‘immersed’, corresponding to its location above or within the surface layer. The results particularly demonstrate the physical importance of the singular flow features and physical implications of the elevated critical layer in the limit of the unsteadiness tending to zero. These agree with the variational ...
A Study Of Energy Transfer Of Wind And Ocean Waves, Shahrdad Sajjadi, Mason Bray
A Study Of Energy Transfer Of Wind And Ocean Waves, Shahrdad Sajjadi, Mason Bray
Publications
To develop a better understanding of energy transfer between wind and different types of waves a model was created to determine growth factors and energy transfers on breaking waves and the resulting velocity vectors. This model was used to build on the research of Sajjadi et al (1996) on the growth of waves by sheared flow and takes models of wave velocities developed by Weber and Melsom (1993) and end energy transfer by Sajjadi, Hunt and Drullion (2012).
Turbulence And Wave Dynamics Across Gas–Liquid Interfaces, Shahrdad Sajjadi, Julian Hunt, Stephen Belcher, Derek Stretch, John Clegg
Turbulence And Wave Dynamics Across Gas–Liquid Interfaces, Shahrdad Sajjadi, Julian Hunt, Stephen Belcher, Derek Stretch, John Clegg
Publications
Mechanisms are reviewed here for the distortion of turbulent flows near thin density interfaces and their effects on transfer processes across them. Firstly the results of rapid distortion calculations show how the in homogeneous eddy structure depends on whether the turbulence is generated above or below the interface, or in both regions. The flow is unstratified and the buoyancy forces are stable and strong enough relative to the inertial forces that the interface is continuous. It is shown that as the surface blocks the vertical turbulent eddy motions, horizontal straining motions are induced which affect the surface viscous layers and ...
Numerical Studies Of Particle Laden Flow In Dispersed Phase, Shahrdad Sajjadi, Rumma Dutta
Numerical Studies Of Particle Laden Flow In Dispersed Phase, Shahrdad Sajjadi, Rumma Dutta
Publications
To better understand the hydrodynamic flow behavior in turbulence, ParticleFluid flow have been studied using our Direct Numerical(DNS) based software DSM on MUSCLQUICK and finite volume algorithm. The particle flow was studied using EulerianEulerian Quasi Brownian Motion(QBM) based approach. The dynamics is shown for various particle sizes which are very relevant to spray mechanism for Industrial applications and Bio medical applications.
Interaction Of TollmienSchlichting Waves In The Air With The Sea Surface, Shahrdad G. Sajjadi, Harihar Khanal
Interaction Of TollmienSchlichting Waves In The Air With The Sea Surface, Shahrdad G. Sajjadi, Harihar Khanal
Publications
No abstract provided.
The Dyad Theory Of Classical And Quantum Physics, Preston Jones
The Dyad Theory Of Classical And Quantum Physics, Preston Jones
Publications
The 4space equations of hydrodynamics, electrodynamics, and quantum mechanics are developed using the dyad calculus. Gravity is found to couple hydrodynamics, electrodynamics, and quantum mechanics through the 4 space metric and differential operator. Expanding the 4space equations of electrodynamics a time varying metric is shown to dissipate electromagnetic energy.
Coupling Of Coamps And Wavetech With Improved Wave Physics, Shahrdad Sajjadi, Pat Fitzpatrick, Gueorgui Mostovoi, Yongzuo Li, Matt Bettencourt
Coupling Of Coamps And Wavetech With Improved Wave Physics, Shahrdad Sajjadi, Pat Fitzpatrick, Gueorgui Mostovoi, Yongzuo Li, Matt Bettencourt
Publications
The Model Coupling Executable Library (MCEL), developed at the University of Southern Mississippi's Center of Higher Learning, has been successfully used to couple the Coupled Ocean/Atmospheric Mesoscale Prediction System (COAMPS) and the ocean wave model WAVEWATCH. An example of its application is shown for Hurricane Gordon, showing that twoway coupling results affects boundary layer physics differently than oneway coupling  in this case, resulting in larger o z and, consequently, larger surface fluxes and a more intense hurricane. However, since analyzing MCEL is difficult because the wave physics is inaccurate, improvements to the wave algorithms are also part of ...