GAMM2025

Session

S09: Laminar flows and transition

S09

10 Apr 2025, 14:00

Lecture and Conference Centre

Conveners

S09: Laminar flows and transition: S09.01

• Krzysztof Jóźwik

S09: Laminar flows and transition: S09.02

• Ryszard Andrzej Białecki

Description

This section will focus on the analysis and modeling of transition from laminar to turbulent flow using DNS, LES, RANS equations, and experiments. Contributions are expected in, but not limited to, the following topics: stability of incompressible and compressible flows, fundamental study of the dynamics of transition, influence of the wall roughness on transition, transition modelling for LES and RANS equations, transition in flows with complex geometries, subcritical transition.

245. Possible predictors of cerebrovascular accidents in paediatric patients with PHACES syndrome: in-silico investigations

Damian Obidowski

10/04/2025, 14:00

Background: PHACES syndrome is regarded as a rare condition with associated disorders that affects multiple parts of the child's organism. The presence of this syndrome can be identified through a range of manifestations, including cardiac and arterial anomalies, ocular anomalies or even dermatological issues. The risk of cerebrovascular accident (CVA) resulting from PHACES syndrome is...

244. FSI simulation represents a novel and efficacious approach for evaluating the management of giant intracranial aneurysms

Piotr Reorowicz

10/04/2025, 14:40

Background: Rupture of giant intracranial aneurysm (GIA, aneurysm larger than 25 mm) can result with either serious brain damage or death. Bypassing is one of the available methods to prevent the aneurysm from rupture. This involves neurosurgeons carefully cutting off the blood inflow to the aneurysm sac, while also creating an additional connection to the distal arteries. It is thought that...

243. Numerical assessment of changes in blood flow hemodynamics after varied virtual endovascular procedures of treating the cerebral aneurysms

Zbigniew Tyfa

10/04/2025, 15:00

Background: It is estimated that 25-50\% of cerebral aneurysm rupture cases end up with the patient death, while around 50\% of survivors is left with permanent brain damage. Thus, it is extremely important to secure the aneurysm before it ruptures. Each endovascular treatment procedure can be carried out with varied implantable devices and the final choice of the treatment method is done by...

246. Numerical Investigation of the Effect of Flow Vorticity on Red Blood Cell Orientation and Deformation

Nico Dirkes

10/04/2025, 15:20

Flow-induced red blood cell damage (hemolysis) occurs when flow forces induce excessive deformation or rupture of red blood cells (RBCs). While physiological flow conditions are generally well tolerated by RBCs, blood-handling medical devices can expose them to high stresses. Hemolysis is therefore a key factor in the design process of ventricular assist devices.

The numerical prediction...

247. Noninvasive assessment of artery wall stiffness

Ryszard Andrzej Białecki

10/04/2025, 15:40

The arterial walls become less flexible as individuals age or due to specific diseases. This leads to the heart pressure wave being less dampened, potentially damaging the sensitive tissues of organs such as the brain and kidneys. Additionally, the pressure wave reflected from the arterial branches combines with the primary wave from the heart, leading to hypertension. The traditional method...

248. Mass transport of a two phase flow through a converging gap with one moving wall

Matthias Graf

10/04/2025, 16:30

Mechanical seals are designed to separate two fluid phases from each other, exemplified by the separation of ambient air and hydraulic oil in hydraulic cylinder applications. These seals necessarily include a converging gap, even at a microscopic level. During operation, a rod in contact with both phases moves through this converging gap. Practically, during a rod instroke motion, a thin film...

249. Unveiling the Edge: Streamwise Localized Solutions and the Nature of Turbulence in Square-Duct Flow

Stanislaw Gepner

10/04/2025, 16:50

Several canonical flows, particularly the square-duct flow, have laminar solutions that remain stable to small disturbances regardless of the Reynolds number. Consequently, the laminar solution remains an attractor in its finite neighborhood, and any non-laminar states are related to the emergence of unstable, invariant solutions that remain separated, in the linear sense, from the laminar...

250. Experimental validation of a CFD model of blood flow in a myocardial bridge

Bartlomiej Melka

10/04/2025, 17:10

Diseases of the human circulatory system are the leading cause of mortality worldwide. Early diagnosis can significantly reduce the risk of developing cardiovascular diseases and their consequences. Computational Fluid Dynamics (CFD) is a computer-aided technology that can be applied in cardiology as a prognostic and diagnostic tool for specific diseases, based on analyzing blood flow...

251. Numerical investigation of nanofluid heat transfer and fluid flow in a microchannel with an elastic baffle

Tarek Bouzennada