Systematic Analysis of Scale Effects on Form Factor
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Mobility engineering (MPMOB), MSc
Publicerad
2023
Författare
Argyros, Minas
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The purpose of the present master thesis is to investigate the difference between model scale and
full scale form factor Computational Fluid Dynamics (CFD) computations, using a new established
method. This method called the two-form factor method (or 2-k method) exposed in two recent research
papers shows improvements in the accuracy of form factor estimation, providing consequently
better results by applying the full scale process, especially in case of stern flow separation phenomena,
such as bubble type flow separation and recirculation type flow separation. The present master thesis
will investigate this form factor procedure using five benchmark hulls, as well as two commercial
hulls being provided by the database of FORCE Technology with the aim of having better insights
about the aforementioned investigated phenomena. First of all, Verification and Validation (V&V)
of the CFD results is executed by comparing the CFD form factor results obtained with the available
model scale experimental results. Furthermore, a systematic analysis of changing the scale factor
of the test cases is applied in order the scale effects to be studied. Moreover, sensitivity analysis of
different roughness heights is implemented so as the effect of the equally distributed roughness to
be investigated in full scale CFD computations. All in all, implementing the systematic analysis in
scale, roughness and draft variations, the results show that the two form factor method is considered
an holistic and trustworthy method which can provide reliable prediction of form factor even for the
case of intense turbulence phenomena in the wake of transom.
Beskrivning
Ämne/nyckelord
CFD , Systematic analysis , Scale effects , Form factor , 2-k method