# Denis AslangilUniversity of Alabama | UA

Denis Aslangil

Doctor of Philosophy

## About

23

Publications

2,183

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137

Citations

Citations since 2017

## Publications

Publications (23)

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

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...

Effects of Atwood and Reynolds numbers on the evolution of buoyancy-driven homogeneous variable-density turbulence - Volume 895 - Denis Aslangil, Daniel Livescu, Arindam Banerjee

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...

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...

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...

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...

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),...

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...

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...