Denis Aslangil

Denis Aslangil
University of Alabama | UA

Doctor of Philosophy

About

23
Publications
2,183
Reads
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137
Citations
Citations since 2017
22 Research Items
137 Citations
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2017201820192020202120222023010203040

Publications

Publications (23)
Conference Paper
Full-text available
The coupled effects of the variable-density and background stratification strength on the growth of the fully compressible single-mode two-fluids Rayleigh-Taylor instability (RTI) are examined using direct numerical simulations (DNS) with varying Atwood and background isothermal Mach number values. The Hydrodynamics Adaptive Mesh Refinement Simulat...
Article
The dynamics of an interfacial flow that is initially Rayleigh-Taylor unstable but becomes statically stable for some intermediate period due to the reversal of the externally imposed acceleration field is studied. We discuss scenarios that consider both single and double-acceleration reversals. The accel-decel (AD) case consists of a single revers...
Preprint
Full-text available
A number of recent studies have proposed that linear representations are appropriate for solving nonlinear dynamical systems with quantum computers, which fundamentally act linearly on a wave function in a Hilbert space. Linear representations, such as the Koopman representation and Koopman von Neumann mechanics, have regained attention from the dy...
Conference Paper
Full-text available
View Video Presentation: https://doi.org/10.2514/6.2022-0456.vid Rayleigh-Taylor instability (RTI) occurs at the interface separating two fluids subjected to acceleration when the directions of the density gradient and the acceleration have opposite signs. Most of the previous scientific literature investigated the RTI under the incompressible assu...
Conference Paper
Full-text available
Deep learning has shown the potential to significantly accelerate numerical simulation of fluids without sacrificing accuracy, but prior works are limited to stationary flows with uniform density. In real-world engineering applications, turbulent flows are mostly three-dimensional, non-stationary and have variable-density. Here we propose Taylor-Ne...
Article
Full-text available
We investigate relationships between statistics obtained from filtering and from ensemble or Reynolds-averaging turbulence flow fields as a function of length scale. Generalized central moments in the filtering approach are expressed as inner products of generalized fluctuating quantities, q ′ ( ξ , x ) = q ( ξ ) − q ¯ ( x ), representing fluctuati...
Preprint
Full-text available
We investigate relationships between statistics obtained from filtering and from ensemble or Reynolds-averaging turbulence flow fields as a function of length scale. Generalized central moments in the filtering approach are expressed as inner products of generalized fluctuating quantities, $q'(\xi,x)=q(\xi)-\overline q(x)$, representing fluctuation...
Conference Paper
Full-text available
The effects of acceleration reversal on the evolution of the buoyancy-driven homogeneous variable-density turbulence (HVDT) is studied by using high-resolution direct numerical simulations. In the HVDT configuration, a heterogeneous mixture of random patches of two miscible fluids with different densities is initially at rest within a triply period...
Conference Paper
Numerical modeling of different structural materials that have highly nonlinear behaviors has always been a challenging problem in engineering disciplines. Experimental data is commonly used to characterize this behavior. This study aims to improve the modeling capabilities by using state of the art Machine Learning techniques, and attempts to answ...
Article
We present our findings from a numerical investigation of the acceleration-driven Rayleigh-Taylor Instability, modulated by varying periods without an applied acceleration field. It is well known from studies on shock-driven Richtmyer-Meshkov instability that mixing without external forcing grows with a scaling exponent as ~ t^{0.20-0.28}. When the...
Preprint
Full-text available
Numerical modeling of different structural materials that have highly nonlinear behaviors has always been a challenging problem in engineering disciplines. Experimental data is commonly used to characterize this behavior. This study aims to improve the modeling capabilities by using state of the art Machine Learning techniques, and attempts to answ...
Article
Full-text available
Effects of Atwood and Reynolds numbers on the evolution of buoyancy-driven homogeneous variable-density turbulence - Volume 895 - Denis Aslangil, Daniel Livescu, Arindam Banerjee
Preprint
The evolution of buoyancy-driven homogeneous variable-density turbulence (HVDT) at Atwood numbers up to 0.75 and large Reynolds numbers is studied by using high-resolution Direct Numerical Simulations. To help understand the highly non-equilibrium nature of buoyancy-driven HVDT, the flow evolution is divided into four different regimes based on the...
Article
The effects of different initial density distributions on the evolution of buoyancy-driven homogeneous variable-density turbulence (HVDT) at low (0.05) and high (0.75) Atwood numbers are studied by using high-resolution direct numerical simulations. HVDT aims to mimic the acceleration-driven Rayleigh–Taylor and shock-driven Richtmyer-Meshkov instab...
Chapter
Full-text available
In this chapter, we discuss density-ratio effects on the life cycle of buoyancy-driven homogeneous variable-density turbulence (HVDT) by using high-resolution (\(2048^3\)) Direct Numerical Simulations (DNS). Two density ratios 1.105 : 1 and 7 : 1 are considered for analysis. In HVDT, the acceleration field is applied to a triply periodic domain in...
Preprint
Full-text available
The effects of different initial density distributions on the evolution of buoyancy-driven homogeneous variable-density turbulence (HVDT) at low (0.05) and high (0.75) Atwood numbers are studied by using high-resolution direct numerical simulations. HVDT aims to mimic the acceleration-driven Rayleigh-Taylor and shock-driven Richtmyer-Meshkov instab...
Article
Full-text available
We present a study of buoyancy-driven variable-density homogeneous turbulence, using a two-point spectral closure model. We compute the time-evolution of the spectral distribution in wave number k of the correlation of density and specific volume b(k), the velocity associated with the turbulent mass flux a(k), and the turbulent kinetic energy E(k),...
Preprint
Full-text available
We present a study of buoyancy-driven variable-density homogeneous turbulence, using a two-point spectral closure model. We compute the time-evolution of the spectral distribution in wavenumber $k$ of the correlation of density and specific-volume $b(k)$, the mass flux $\bm{a}(k)$, and the turbulent kinetic energy $E(k)$, using a set of coupled equ...
Article
The influence of initial conditions on miscible incompressible baroclinically driven Rayleigh-Taylor instability undergoing nonuniform acceleration is explored computationally using an implicit large eddy simulation (ILES) technique. We consider the particular case of evolution during multiple reversals of acceleration direction, where the flow is...

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