Nikolopoulos Nikolaos

Dr. Nikolopoulos Nikolaos

orcid

Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 October 2014 in Advances in Colloid and Interface Science
Verified
Journal Article
Open access
IMIlias Malgarinos
Ilias Malgarinos
Nikolopoulos NikolaosNikolopoulos Nikolaos
Nikolopoulos Nikolaos
Marco MarengoMarco Marengo
Marco Marengo
Carlo AntoniniCarlo Antonini
Carlo Antonini
Manolis GavaisesManolis Gavaises
Manolis Gavaises
In this study,a novel numerical implementation for the adhesion of liquid droplets impacting normally on solid dry surfaces is presented. The advantage of this new approach, compared to the majority of existing models, is that the dynamic contact angle forming during the surface wetting process is not inserted as a boundary condition, but is derived implicitly by the induced fluid flow characteristics (interface shape) and the adhesion physics of the gas-liquid-surface interface (triple line), starting only from the advancing and receding equilibrium contact angles. These angles are required in order to define the wetting properties of liquid phases when interacting with a solid surface. The physical model is implemented as a source term in the momentum equation of a Navier-Stokes CFD flow solver as an "adhesion-like" force which acts at the triple-phase contact line as a result of capillary interactions between the liquid drop and the solid substrate. The numerical simulations capture the liquid-air interface movement by considering the volume of fluid (VOF) method and utilizing an automatic local grid refinement technique in order to increase the accuracy of the predictions at the area of interest, and simultaneously minimize numerical diffusion of the interface. The proposed model is validated against previously reported experimental data of normal impingement of water droplets on dry surfaces at room temperature. A wide range of impact velocities, i.e. Weber numbers from as low as 0.2 up to 117, both for hydrophilic (θadv=10°-70°) and hydrophobic (θadv=105°-120°) surfaces, has been examined. Predictions include in addition to droplet spreading dynamics, the estimation of the dynamic contact angle; the latter is found in reasonable agreement against available experimental measurements. It is thus concluded that theimplementation of this model is an effective approach for overcoming the need of a pre-defined dynamic contact angle law, frequently adopted as an approximate boundary condition for such simulations. Clearly, this model is mostly influential during the spreading phase for the cases of low We number impacts (We<˜80) since for high impact velocities, inertia dominates significantly over capillary forces in the initial phase of spreading.

1 August 2006 in Journal of Colloid and Interface Science
Verified
Journal Article
Closed access
ATAndreas Theodorakakos
Andreas Theodorakakos
TOT. Ous
T. Ous
Manolis GavaisesManolis Gavaises
Manolis Gavaises
JNJ.M. Nouri
J.M. Nouri
Nikolopoulos NikolaosNikolopoulos Nikolaos
Nikolopoulos Nikolaos
HYH. Yanagihara
H. Yanagihara

1 January 2007 in International Journal of Heat and Mass Transfer
Verified
Journal Article
Closed access
Nikolopoulos NikolaosNikolopoulos Nikolaos
Nikolopoulos Nikolaos
ATAndreas Theodorakakos
Andreas Theodorakakos
GBG. Bergeles
G. Bergeles

1 September 2015 in Fuel
Verified
Journal Article
Closed access
Nikolopoulos NikolaosNikolopoulos Nikolaos
Nikolopoulos Nikolaos
IVIoannis Violidakis
Ioannis Violidakis
EKEmmanouil Karampinis
Emmanouil Karampinis
MAMichalis Agraniotis
Michalis Agraniotis
CBChristian Bergins
Christian Bergins
Emmanuel KakarasEmmanuel Kakaras
Emmanuel Kakaras

1 August 2015 in Fuel
Verified
Journal Article
Closed access
Konstantinos AtsoniosKonstantinos Atsonios
Konstantinos Atsonios
PGP. Grammelis
P. Grammelis
SAS.K. Antiohos
S.K. Antiohos
Nikolopoulos NikolaosNikolopoulos Nikolaos
Nikolopoulos Nikolaos
Emmanuel KakarasEmmanuel Kakaras
Emmanuel Kakaras

1 June 2009 in Computers & Fluids
Verified
Journal Article
Closed access
Nikolopoulos NikolaosNikolopoulos Nikolaos
Nikolopoulos Nikolaos
KNK.-S. Nikas
K.-S. Nikas
GBG. Bergeles
G. Bergeles