Numerical simulations of primary break-up in two-phase flows

Liquid-Gas interactions and break-up processes are found in many technological and environmental applications, from Internal Combustion and Gas Turbine engines to food processing and manufacturing. Their complete characterisation at realistic Weber and Reynolds numbers is not possible, due to the vast range of scales integrated and the requirement of a ’minimum’ computational mesh size to capture these scales. To this day, a number of questions remain unanswered, with relative research still ongoing. It is crucial to understand such phenomena so that any technological applications can be optimised and the environmental impact can be reduced. Currently, there is a high need to develop appropriate numerical modelling tools that provide both mass conservation and accurate interface topological properties. Two common interface modelling approaches are the Volume of Fluid and the Level Set, typically coupled into CLSVOF methods to ensure improved surface representation and good mass properties. In this work, a novel in-house Mass Conservative Level Set (CMLS) method is developed and validated extensively. The CMLS novelty is in the Level Set coupling with the Volume of Fluid, being processed only when necessary, providing a faster and more robust approach. Doing so, some numerically imposed limitations due to the ’physics’ and ’stability’, are overcome. The novel CMLS is employed for primary break-up investigations, in a single liquid droplet and jets. Single droplet break-up remains a benchmark test case, as it provides good foundations for liquid jet break-up and spray atomisation modelling. In such processes, the main effective parameters considered are the Weber and Reynolds numbers, along with the Ohneshorge (droplets) and Dynamic Pressure ratio (jets). Contrary to most studies, this work employs the surface density evolution using the Σ − Y model. The droplet break-up cases, show a strong correlation between the break-up initiation time and the Ohneshorge number, whilst as the Weber increases so does the droplet complete break-up time. This is of particular interest as at higher Weber numbers, surface density effects be- come negligible and thus by definition the complete break-up time should in fact decrease. However, similar behaviours were noted in previous studies. The droplets surface density evolution shows a ’quasi-independent’ relationship with the gas Weber. In the jets, a strong correlation between the surface density and ligament formation exists. However, the surface density is ’quasi-independent’ of the liquid Reynolds and the gas Weber. The gas boundary layer presence in jets, shows to both reduce and delay any liquid/gas inter- face perturbations and the potential break-up. To summarise, the present investigations are generally in good agreement with previous studies, with minimal contradictions in cases. The novel CMLS capabilities show promising results both in the two- and three- dimensional space. This work provides good foundations for a slightly alternative research approach in two-phase flows modelling.Open Acces

AN ANALYSIS OF FIGURATIVE LANGUAGE IN THE SOUNDTRACKS OF THE GREATEST SHOW MAN : A MILLION DREAMS

The purpose of this study is to identify the types of figurative language and analyze the contextual meaning of the figurative language used in the soundtrack of Showman A Million Dreams. This thesis uses a qualitative descriptive method. The source of the research data used is the lyrics in the Greatest Showman Soundtrack: A Million Dreams. The data collection method used selected songs from the soundtrack of the film The Greatest Showman: A Million Dreams. The collected data was then classified according to the differences, presented in the form of a table and found the types of figurative language and the metaphorical meaning of each song. Based on the analysis in this thesis, found 7 figurative language styles out of 53 which have been interpreted from 21 lyrics of the song A Million Dreams. The seven types are imagery, personification, symbol, paradox, hyperbole, repetition, and metaphor. The researcher found that from 53 figurative types, 18 types are imagery, 4 types are personification, 14 types are symbols, 2 types are paradoxes, 6 types are hyperbole, 8 types are repetition and 1 type includes metaphor. The researcher also draws the conclusion that literary creation does not only consist of entertainment purposes, but also moral values and educational essence that are very useful for English language learners such as virtue values and  figurative languag

On Spanish Dvandva and its restrictions

As noted by Bauer, real dvandva compounds –that is, coordinative compounds that properly express the aggregation of two different entities, not the intersection of properties in one entity– are extremely rare in English or Spanish. This article explores the empirical domain of dvandva compounding in Spanish, and notes that they are productive when not used as heads within their phrases. We propose that the explanation for this is that Spanish can only productively build dvandva compounds using flat structures without internal hierarchy. This causes the compound to look externally for a head noun that defines the interpretation of the relation established between the two members of the dvandva. The proposal also explains why proper names is preferred in dvandva compounding, given that they do not denote properties

Prefixation in modern greek dialects: synchronic and diachronic perspective

This thesis deals with prefixation cases in Modern Greek Dialects from a synchronic and diachronic point of view. In particular, the following dialectal morphemes: akro-, moro-, plako-, s(j)o-/sa- and hamo- are investigated with respect of their historical development and their phonological, structural and semantic differences in synchronic terms. Prefixization (c.f. Amiot 2005) as a diachronic crossing from compounding to prefixation shows that there is no clear borderline between the two processes (Booij 2005, Bauer 2005, Ralli to appear). According to this phenomenon, a morpheme shows divergence with respect to its ancestor, loses its lexical independence (Iacobini 2004), and may be subject to phonological erosion. It is generally accepted that grammaticalization occurs if certain criteria are satisfied (Lehmann 1985, Hopper & Traugott 1983, Hopper 1991, Heine & Kuteva 2002, Heine 2003, Amiot 2005, Giannoulopoulou 2006, Αnastasiadi-Symeonidi 2008, van Goethem 2008). As far as prefixization is concerned, and with some degree of variation from one author to another, there is more or less agreement on the following general criteria: a) phonological erosion, b) desemanticization, c) decategorialization, d) shrinking of syntagmatic weight, e) coalescence, f) extension of the morphological combinatorial properties. In this study, I try to answer three important questions: a) what are the specific parameters which may induce prefixization out of compounding? b) Are these parameters the same for all the range of grammaticalization phenomena, or are they restricted to morphology? c) Is there a particular order according to which these parameters seem to play a role in morphologization? I argue that if we deal with morphology the parameters which lead to the completion of a morphologization process have to be morphological in nature. Other parameters may trigger the process, or may play a role during the process, but do not guarantee completion. Within this spirit, I propose that the general grammaticalization parameters which are involved in prefixization are desemanticization and phonological erosion, but the specific morphological parameters which are crucial for determining the final stage of prefixization are related to: a) the increase of productivity, b) the expansion of morphological combinatorial properties. Evidence from the history of Greek and its Modern Greek dialects illustrate the above proposals.Στην παρούσα διατριβή επιχειρείται η συγχρονική και διαχρονική προσέγγιση φαινομένων προθηματοποίησης στις νεοελληνικές διαλέκτους. Συγκεκριμένα, μελετώνται τα διαλεκτικά μορφήματα ακρο-, μωρο-, πλακο-, σ(ι)ο-/σα-, χαμο- ως προς την ιστορική τους εξέλιξη, και τις φωνολογικές, δομικές και σημασιολογικές τους αποκλίσεις σε συγχρονικό επίπεδο. Η μετάβαση από τη σύνθεση στην παραγωγή, δηλαδή η προθηματικοποίηση (βλ. Amiot 2005), αποδεικνύει ότι τα όρια ανάμεσα στις δύο διαδικασίες δεν είναι σαφώς διακριτά (Booij 2005, Bauer 2005, Ralli 2010). Κατά την προθηματικοποίηση, ένα μόρφημα αποκλίνει από το λεξηματικό του πρόγονο, χάνει την αυτονομία του (Iacobini 2004) και είναι δυνατό να υπόκειται σε φωνολογικές αλλαγές. Είναι γενικώς παραδεκτό ότι η γραμματικοποίηση επιτελείται, εφόσον πληρούνται ορισμένες προϋποθέσεις (Lehmann 1985, Hopper & Traugott 1983, Hopper 1991, Heine & Kuteva 2002, Heine 2003, Amiot 2005, Giannoulopoulou 2006, Αναστασιάδη-Συμεωνίδη 2008, van Goethem 2008). Οι προτεινόμενες γενικές παράμετροι για την προθηματικοποίηση από τη διεθνή βιβλιογραφία είναι οι ακόλουθες: α) φωνολογική διάβρωση, β) αποσημασιοποίηση, γ) αποκατηγοριοποίηση, δ) περιορισμός συντακτικού βάρους, ε) ανάμειξη, στ) διεύρυνση συνδυαστικών μορφολογικών ιδιοτήτων. Στη μελέτη αυτή, προσπαθώ να απαντήσω σε τρεις σημαντικές ερωτήσεις: α) Ποιες είναι οι εξειδικευμένες παράμετροι που ερμηνεύουν τη μετάβαση από τη σύνθεση στην προθηματοποίηση; β) Οι παράμετροι αυτές είναι ίδιες για όλα τα φαινόμενα γραμματικοποίησης ή περιορίζονται στο πεδίο της μορφολογίας; γ) Ποια είναι η ιεράρχηση των συγκεκριμένων παραμέτρων κατά τη μορφολογικοποίηση; Στο πεδίο της μορφολογίας, υποστηρίζω ότι ο μορφολογικός παράγοντας έχει αποφασιστική σημασία για την περάτωση μιας διαδικασίας μορφολογικοποίησης. Είναι δυνατό άλλες παράμετροι να κινητοποιούν ή να συνεισφέρουν στην εξέλιξη της διαδικασίας, αλλά δεν μπορούν να εγγυηθούν την ολοκλήρωση αυτής. Υπό αυτήν την έννοια, προτείνω ότι οι γενικές παράμετροι που εμπλέκονται είναι η επανασημασιοποίηση και η διάβρωση, ενώ οι εξειδικευμένες μορφολογικές παράμετροι που απαντούν σε τελικό στάδιο της προθηματικοποίησης είναι: α) η αύξηση της παραγωγικότητας, β) η διεύρυνση των μορφολογικών συνδυαζόμενων βάσεων. Τόσο τα εξεταζόμενα διαχρονικά δεδομένα της Ελληνικής γλώσσας, όσο και τα εξεταζόμενα συγχρονικά δεδομένα από τη διαλεκτική ποικιλία της νέας Ελληνικής επιβεβαιώνουν τις παραπάνω θέσεις

Constructional change on the contentful-procedural gradient. The case of the -idz(o) construction in Griko

Tis chapter focuses on a rather neglected type of morphological change, that is, the change from derivation to inflection. Contrary to the assumption that derivational patterns usually do not develop any further, this analysis proposes that some derivational constructions may change by acquiring a more functional status, which is characteristic of inflectional categories. Based on the distinction between contentful and procedural constructions, as proposed by Traugott & Trousdale (2013), the emergence of the new constructions can be conceived of as a gradual shif on the contentful-procedural gradient. Te argumentation is based on examination of the -idz(o) constructions in Griko, a Greek-based dialect spoken in South Italy