GAMM2025

Session

S10: Turbulence and reactive flows

S10

8 Apr 2025, 08:30

Lecture and Conference Centre

Conveners

S10: Turbulence and reactive flows: S10.01

• Marta Wacławczyk

S10: Turbulence and reactive flows: S10.02

• Ewa Tuliszka-Sznitko

S10: Turbulence and reactive flows: S10.03

• Marta Wacławczyk

S10: Turbulence and reactive flows: S10.04

• Ewa Tuliszka-Sznitko

S10: Turbulence and reactive flows: S10.05

• Rafał Ślefarski

Description

The topic of this session is the analysis and modeling of turbulent non-reactive and reactive flows based on DNS, LES, RANS, and experiments. A special focus is on fundamentals in turbulence, turbulent reactive flows, turbulent multi-phase flows, turbulence of atmosphere, atmosphere/ocean interaction, modeling and simulation of complex turbulent flows, the interface of numerical algorithms, chemical and physical modeling, as well as high-performance computing with its application to turbulence.

252. Progress in high-moment turbulent scaling laws of wall-bounded shear flows

Martin Oberlack

08/04/2025, 08:30

First shown in Oberlack (2001) and significantly extended to higher moments in Oberlack et al. (2022), we presently show that in near-wall turbulent shear flows, i.e. specifically for the log-region as well as for the core region of a channel flow, streamwise velocity moment scaling laws up to an arbitrary order can be derived using symmetry theory. Recently, we have extended the theory to...

253. Momentum Transfer of Riblets in the Drag Increasing Regime

Natalie Rapp

08/04/2025, 09:10

The pursuit of sustainable mobility requires innovative solutions, one of which involves applying riblets—a specific form of small surface corrugation—to smooth surfaces immersed in turbulent flows. Riblets have demonstrated the ability to reduce friction drag below that of a smooth wall without any external energy input, making them highly promising for industrial applications. Their...

254. Unsteady turbulent energy dissipation in an axisymmetric turbulent wake

Martin Obligado

08/04/2025, 09:30

Axisymmetric turbulent wakes generated by bluff bodies are relevant to several applications, including aviation, road transport, and the design of wind turbine masts, among others. This experimental study focuses on the unsteady properties of turbulence dissipation resulting from the non-equilibrium energy cascade in the turbulent axisymmetric wake. Recent numerical studies (e.g., Goto and...

255. Inverse energy cascade within atmospheric convective structures

Paweł Jędrejko

08/04/2025, 09:50

Atmospheric turbulence is of key importance in numerical weather prediction and climate modeling. Particularly intriguing are the convective structures, which give rise to cloud formations and affect the intra-cloud processes. Although impactful, these can rarely be solved directly and have to be modeled instead. The challenging aspect of atmospheric turbulence is its anisotropy and...

256. Heat transfer in thermally developing, inhomogeneously heated turbulent pipe flows

Leo Bürk

08/04/2025, 10:10

Liquid metals, such as Sodium, Gallium and Gallium alloys have applications as heat transfer fluids in a broad temperature range. They possess low Prandtl numbers, which makes them ideal as a heat transfer medium for applications such as concentrated solar power plants (CSPs). Due to their low Prandtl numbers the heat transfer mechanism for liquid metals is different than for medium or high...

257. Error decomposition of large-eddy simulation applied to turbulent combustion

Bernard Geurts

08/04/2025, 16:30

Turbulent flow is characterized by a wide spectrum of temporal and spatial scales, giving rise to complex dynamics. Turbulent flow often cannot be resolved fully in a direct numerical simulation (DNS) and coarsened approximate models for the dynamics at larger scales only, are considered. An important reduced-order model is so-called large-eddy simulation (LES), motivated through the...

258. Application of Extended Large-Eddy Simualtion (XLES) to turbulent channel flow

Pavle Marinković

08/04/2025, 17:10

Large-Eddy Simulation (LES) are state-of-the-art in engineering applications of Computational Fluid Dynamics (CFD). Fine grids offer high accuracy at high cost, whereas coarse grids require additional modeling assumptions that limit predictive capabilities. This dilemma is addressed by Extended LES (XLES). The original XLES formulation [1] utilized the One-Dimensional Turbulence (ODT) model...

259. Investigating the Impact of Forcing Mechanisms on Passive Scalar Mixing Using Stochastic One-Dimensional Turbulence

Abhishek Joshi

08/04/2025, 17:30

This study presents a numerical investigation of passive scalar mixing in Homogeneous Isotropic Turbulence(HIT). Different volumetric forcing schemes have been used in the literature, but the side effects are rarely discussed, either because these are assumed irrelevant or because it is too costly to conduct such analysis with a high-fidelity model. Nevertheless, various HIT forcing schemes...

260. Formulation of an improved wall model for turbulent concentric coaxial pipe flows

Li Toong Yap

08/04/2025, 17:50

Coaxial pipe flow is encountered in many engineering applications, such as in heat exchangers, chemical reactors or cooling systems in nuclear engineering. These applications require an accurate modelling of the momentum transport, as it is a prerequisite for the transport of additional scalar quantities. The presence of an inner curved wall in coaxial pipe flows poses a challenge for...

261. Reconstruction of inhomogeneous turbulence based on stochastic Fourier-type integrals

Felix Lindner

08/04/2025, 18:10

We develop and analyze a random field model for the reconstruction of inhomogeneous turbulence from characteristic flow quantities provided by k-epsilon simulations. The model is based on stochastic integrals that combine moving average and Fourier-type representations in time and space, respectively, where both the time integration kernel and the spatial energy spectrum depend on the...

262. LES/PDF Simulations of Turbulent Reacting Flows

Metin Muradoglu

09/04/2025, 08:30

In turbulent reactive flows, the chemical reactions occur at scales that are even smaller than the smallest turbulence scales. As a result, the highly non-linear chemical reaction source terms appear to be in unclosed (averaged or filtered) form and must be modeled in a similar fashion in both RANS and LES approaches. The probability density function (PDF) method offers a distinct advantage of...

263. CFD Based Kinetic Parameter Estimation Method for Arbitrary Reactor Geometries

Muhammad Uzair Qureshi

09/04/2025, 09:10

To estimate the kinetic parameters of surface catalytic reactions, ubiquitously ideal reactor models like the CSTR, stagnation point flows, or the plug flows are exploited. This allows the system to be governed by either analytical or a simple ODE based solution. However, modern in-situ atomic scale surface characterization experiments seldom allow such flow geometries, e.g. by the need to...

264. Development of detailed surface reaction mechanism for methanation process based on experiments

Rakhi

09/04/2025, 09:30

The pressure to reduce greenhouse gas emissions is growing, which demands new and innovative technologies to produce mobile as well as stationary energy. The CO2 methanation offers a pathway to reduce greenhouse gas emissions by directly converting CO2 to CH4. This also plays a crucial role in "power-to-gas" (P2G) technologies by providing an approach to store excess renewable energy in the...

265. Kinetic investigation of methanation over Ni-CeO2 using a one-dimensional model

D. Ibrayeva

09/04/2025, 09:50

The methanation of carbon monoxide (CO) and carbon dioxide (CO₂) over nickel-based catalysts plays a critical role in addressing global energy and environmental challenges. As a cornerstone process in synthetic natural gas (SNG) production, the catalytic methanation enables renewable energy storage and the use in transportation. It also underpins CO₂ utilization strategies, converting...

266. Influence of porous material on the flow behind a backward-facing step: experimental study

Lukasz Klotz

09/04/2025, 16:30

We investigate effect of porous insert located upstream of the separation edge of a backward-facing step (BFS) in early transitional regime as a function of Reynolds number. This is an example of hydrodynamic system that is a combination of separated shear flow with large amplification potential and porous materials known for efficient flow destabilisation. Spectral analysis reveals that...

267. Gas transfer through sea surface - turbulence and surfactan

Jacek Piskozub

09/04/2025, 17:10

The air-sea gas flux is proportional to the difference of partial pressure between the sea-water and the overlying atmosphere multiplied by gas transfer velocity k, a measure of the effectiveness of the gas exchange. Because wind is the source of turbulence making the gas exchange more effective, k is usually parameterized by wind speed. Unfortunately, measured values of gas transfer velocity...

268. Analysis and parametrization of turbulence in stably-stratified atmospheric boundary layers

Marta Wacławczyk

09/04/2025, 17:30

Atmospheric boundary layer (ABL) is a region is the lowest part of the Earth's atmosphere, where interactions between the surface and the atmosphere play a crucial role in shaping weather patterns, climate processes, and air quality. Stably stratified ABL, form mostly over night due to surface radiative cooling, they also prevail in the snow-covered polar regions. Under the stable...

269. Turbulence statistics in thunderclouds

Joydeep Sarkar

09/04/2025, 17:50

Cumulonimbus clouds, commonly called thunderclouds are widely associated with thunder and lightning. Even though they develop originally from cumulus clouds, very little is known about their behavior, especially in terms of turbulent statistics. In this study, using data obtained from measurement campaigns, we analyze, in parallel, the variation of the electric field, temperature, and wind...

270. Modelling transient, compressible and subcritical vessel outflows

Michael-David Fischer

09/04/2025, 18:10

The outflow of a gas from a pressurised vessel is one of the classical fundamental problems in fluid mechanics. However, the compressible and subcritical case is more complex than one might think and there is no general analytical solution. This case was examined in more detail.

Based on the Bernoulli’s equation, a fast and accurate model for the prediction of transient gas outflow from...

271. The Influence of Hydrocarbon Additives on Laminar Burning Velocity and NOx Emissions in Hydrogen Combustion

Abdelkader Hemaizia

10/04/2025, 08:30

Hydrogen role in energy systems has become a central focus of global interest due to its potential as a zero-carbon fuel. Hydrogen provides a transformative alternative to hydrocarbons, exhibiting unique combustion properties. However, its high reactivity often leads to combustion instabilities, e.g., flame flashback or blowout, which increase the risk of combustor failure. Therefore, to...

272. Towards the use of HiPS as scalar mixing model in a full engine cycle simulation

Tommy Starick

10/04/2025, 08:50

Turbulent mixing is an ubiquitous phenomena and plays an important role in our everyday life and numerous industrial applications. The numerical study of turbulent mixing processes poses a standing challenge since it requires a capture of all relevant length and time scales while still being computationally feasible. To eliminate this dilemma, an efficient and full-scale resolving modeling...

273. Effect of swirl flame shaping on emissions in CH4-NH3 co-firing - experimental and numerical study

Rafał Ślefarski

10/04/2025, 09:10

The study examines the impact of geometric reduction and simplification of the swirl burner on the morphology of the lean flame and the NO emissions produced when ammonia is gradually added to fuel. Analyses were conducted in both two-dimensional and three-dimensional formats where the most commonly employed geometric reductions, axisymmetric swirl and periodicity, were subjected to the...

758. The Evolution of André Lévêque's Thermal Boundary-Layer Solution

Niall McMahon

10/04/2025, 09:30

In 1928, André Lévêque defended his PhD thesis in Paris. Its title was Les Lois de la Transmission de Chaleur par Convection - The Laws of Convective Heat Transfer - and it was published that same year in Annales des Mines, the famous French mining engineering journal. Lévêque's contribution was a new way to think about how heat moves across a thin layer of fluid close to a wall. Lévêque is...