Golshan Koviji Roomina
Country
Iran
Education

Master of The field of fundamental physics at the University PAYAME Noor University of Tabriz, Iran.

Bachelors of Atomic physics at SHAHID MADANI AZARBAIJAN University, Tabriz, Iran.

Curriculum Vitae
ESR13 - Investigation on the way to include water droplet heterogeneous nucleation classical and non-classical models inside direct numerical simulation codes describing turbulent mixing and entrainment at the boundary of a cloud
Objectives

The aim is to propose numerical new procedures to implement droplet nucleation models inside codes where the cloud interface is studied by coupling the Eulerian description of the turbulent velocity and water vapour fields with a Lagrangian ensemble of cloud water droplets that can undergo stochastic nucleation, as well as growth and shrinking by condensation and evaporation, respectively.

Expected Results

Enhanced structure of physical model matching droplets nucleation, condensation growth, coalescence and turbulent transport. Algorithms and software tools to handle relevant DNS codes.

Planned secondment(s)
  • ISAC (Torino)              Month 18-19: nucleation modelling and atmospheric flows
  • MPIM (Bonn)               Month 20: simulations of clouds
  • MPG (Goettingen)       Month 21: experiments on aerosol and nucleation in the cloud chamber
  • INRIM (Torino)             Month 29: model calibration
  • RP (Torino)                 Month 30: environmental aerosol data scquisition
Comments

Born in Tabriz, IRAN, I speak Azeri, Turkish, Persian, English, and a little bit of Italian. I am an international swimmer and I have the third degree of swimming coach and I also have black belt in karate. I really enjoy teaching people, which is something that I have pursued throughout my life.  

As a primary student I felt great passion towards experimental sciences like Physics and Chemistry, which caused me to dedicate a lot of my time to these experimental activities. During these years physics was the subject where most of my interest lied. Therefore, I got more and more motivated to enroll to the department of atomic physics in the most competitive universities. I have a background in Physics with a master thesis in the field of fundamental physics (New Potential with the Oscillator Spectrum). My previous work experience was in the Coherent state theory, Non-linear system and coherent related state, Electro optic effects and electro absorption process. In addition, I have a great passion for physics of the atmosphere or environmental physics, chaotic systems or turbulence, fluid dynamics or statistical mechanics to name but a few.

And finally, I am writing this comment tab being in Turin, Italy. I got an opportunity to pursue PhD studies in Cloud Physics at Politecnico di Torino as a researcher in the COMPLETE project. I will do my best and I will dedicate my time and energy to make this experience a very valuable one.

 

Email: mina.golshan@polito.it

Publications

Diffusion of turbulence following both stable and unstable step stratification perturbations

Year
2022
Document type
Article
Authors
Luca Gallana, Shahbozbek Abdunabiev, Mina Golshan, Daniela Tordell
Source

Politecnico di Torino

 

The recent paper has been published on Physics of Fluids with a following title:

"Diffusion of turbulence following both stable and unstable step stratification perturbations" 

   Physics of Fluids (2022); https://doi.org/10.1063/5.0090042

     Luca Gallana, Shahbozbek Abdunabiev, Mina Golshan,  Daniela Tordella

The evolution of a two-phase, air and unsaturated water vapor, time decaying, shearless, turbulent layer has been studied in the presence of both stable and unstable perturbations of the normal temperature lapse rate. The top interface between a warm vapor cloud and clear air in the absence of water droplets was considered as the reference dynamics. Direct, three dimensional, numerical simulations were performed within a 6m x 6m wide and 12m high domain, which was hypothesized to be located close to an interface between the warm cloud and clear air. The Taylor micro-scale Reynolds’ number was 250 inside the cloud portion. The squared Froude’s number varied over intervals of [0.4; 981.6] and [-4.0; -19.6]. A sufficiently intense stratification was observed to change the mixing dynamics. The formation of a sub layer inside the shearless layer was observed. The sub-layer, under a stable thermal stratification condition, behaved like a pit of kinetic energy. However, it was observed that kinetic energy transient growth took place under unstable conditions, which led to the formation of an energy peak just below the center of the shearless layer. The scaling law of the energy time variation inside the interface region was quantified: this is an algebraic law with an exponent that depends on the perturbation stratification intensity. The presence of an unstable stratification increased the differences in statistical behavior among the longitudinal velocity derivatives, compared with the unstratified case. Since the mixing process is suppressed in stable cases, small-scale anisotropy is also suppressed.

Microphysical time scales and local supersaturation balance at a warm Cloud Top Boundary

Year
2022
Document type
Article
Authors
Ludovico Fossa', Shahbozbek Abdunabiev, Mina Golshan, Daniela Tordella
Source

The paper on the microphysical time scales has been accepted and is already published on Physics of Fluids (AIP).

Recent results have shown that there is an acceleration in the spread of the size distribution of droplet populations in the region bordering the cloud and undersaturated ambient. We have analyzed the supersaturation balance in this region, which is typically a highly intermittent shearless turbulent mixing layer, under a condition where there is no mean updraft. We have investigated the evolution of the cloud - clear air interface and of the droplets therein via direct numerical simulations. We have compared horizontal averages of the phase relaxation, evaporation, reaction and condensation times within the cloud-clear air interface for the size distributions of the initial monodispersed and polydisperse droplets. For the monodisperse population, a clustering of the values of the reaction, phase and evaporation times, that is around 20-30 seconds, is observed in the central area of the mixing layer, just before the location where the maximum value of the supersaturation turbulent flux occurs. This clustering of values is similar for the polydisperse population but also includes the condensation time. The mismatch between the time derivative of the supersaturation and the condensation term in the interfacial mixing layer is correlated with the planar covariance of the horizontal longitudinal velocity derivatives of the carrier air flow and the supersaturation field, thus suggesting that a quasi-linear relationship may exist between these quantities.

A model for the small scale turbulence production term in the local supersaturation balance at a Cloud Top Boundary

Year
2021
Document type
Article
Authors
Ludovico Fossa, Shahbozbek Abdunabiev, Mina Golshan, Daniela Tordella
Source

ArXiv e-print archive, http://arXiv.org/abs/2108.00817 

The supersaturation local balance equation is considered at a cloud boundary, and the structure of its turbulent production term is inferred from numerical experiments. The transient decay of an unstable-stratified, shearless-mixing layer at a warm cloud top is modeled as an initial value problem, in which the turbulent velocity, the active scalars, and the droplet dynamics are solved concurrently. The evolution of the cloud-clear air interface and the droplets therein is investigated via direct numerical simulations. Both initial monodisperse and polydisperse droplet size distribution cases are treated. We attempt to model the turbulent production of supersaturation - defined as the difference between the time derivative of the supersaturation and the condensation terms - in the mixing layer. The planar averages of the supersaturation production term are clearly correlated with the planar covariance of the computed horizontal velocity derivative and supersaturation fields, thus suggesting that a quasi-linear relationship may exist between these quantities. The value of the non-dimensional proportionality constant is deduced by i) modeling the production term as the interaction of two sinusoidal perturbations with local and global small-scale frequencies, and ii) spatially averaging the production term and the covariance of the supersaturation and the longitudinal velocity derivatives. It has been verified that the value of such proportionality constant does not vary considerably throughout the transient decay and is not sensitive to the initial droplet distribution dispersity.

Intermittency acceleration of water droplet population dynamics inside the interfacial layer between cloudy and clear air environments

Year
2021
Document type
Article
Authors
M. Golshan, Sh. Abdunabiev, M. Tomatis, F. Fraternale, M. Vanni, D. Tordella
Source

International Journal of Multiphase Flow (IJMF)

POLITO group has published a paper in the International Journal of Multiphase Flow (IJMF). The paper concentrates on intermittency acceleration of water droplet population dynamics inside the interfacial layer between cloudy and clear air environments.

Impact of turbulence on cloud microphysics of water droplets population

Year
2019
Document type
Other
Authors
M. Golshan, F. Fraternale, M. Vanni, D. Tordella
Source

72nd Annual Meeting of the APS Division of Fluid Dynamics, 2019. 23 - 26 November 2019. Seattle, USA. 

Cloud-clear air interfaces: Population Balance Equation solutions by considering nucleation information from in-situ measurements, and by modeling the droplet growth on super-saturation fluctuation data from numerical simulation

Year
2019
Document type
Other
Authors
M. Golshan, F. Fraternale, M. Vanni, D. Tordella
Source

17th European Turbulence Conference, 3 - 6 September 2019. Turin, Italy

Water droplets simulation in a warm cloud-like ambient

Year
2018
Document type
Other
Authors
D. Codoni, M. Golshan, V. Ruggiero, M. Iovieno, M. Vanni, D. Tordella
Source

European Mechanics Society, Colloquium 596, Numerical simulations of flows with particles, bubbles and droplets. 9 - 11 May 2018, Venice, Italy. 

Water droplets simulation in a warm cloud like ambient

Year
2018
Document type
Other
Authors
D. Codoni, M. Goshan, V. Ruggiero, M. Vanni, D. Tordella
Source

EGU General Assembly 2018. 8 - 13 April 2018. Vienna, Austria. 

Water droplets simulation in a warm cloud like ambient

Year
2018
Document type
Other
Authors
D. Codoni, M. Golshan, V. Ruggiero, M. Iovieno, M. Vanni, D. Tordella
Source

EGU General Assembly 2018. 8 - 13 April 2018. Vienna, Austria.