{"id":{"repo_id":"greece","oai_identifier":"oai:10442/1708"},"canonical_url":"https://search.dev.ndltd.org/etd/greece/oai:10442/1708","repository":{"repo_id":"greece","name":"Greek National Archive of PhD Theses","base_url":"https://phdtheses.ekt.gr/eadd_oai/request"},"display":{"title":"ΜΕΛΕΤΗ ΔΑΚΤΥΛΙΟΕΙΔΟΥΣ ΔΙΦΑΣΙΚΗΣ ΡΟΗΣ ΣΕ ΟΡΙΖΟΝΤΙΟ ΑΓΩΓΟ","abstract":"TIME RECORDS HAVE BEEN COLLECTED OF LOCAL LIQUID FILM THICKNESS, USING PARALLELWIRE CONDUCTANCE PROBES, IN A NEW 50.8 MM I.D. PIPE LOOP. STATISTICAL ANALYSISOF THESE RECORDS ALLOWS THE STUDY OF CIRCUMFERENTIAL VARIATION OF TIME-AVERAGED THICKNESS AND OF OTHER QUANTITIES. THE POWER SPECTRA SHOW THAT THE DOMINANT FREQUENCY ASSOCIATED WITH LARGE WAVES IS <10 HZ AT LOW GAS VELOCITIES, DISPLAYING A TENDENCY TO INCREASE WITH GAS FLOW RATE. BY COMBINING SIGNAL CROSS-CORRELATION DATA WITH VISUAL OBSERVATIONS, IT IS SHOWN THAT THE DISTURBANCE WAVES TEND TO DEFORM RAPIDLY, MOVE ON A PLANE INCLINED WITH RESPECT TO THE VERTICAL, AND COVER AN INCREASINGLY LARGER PORTION OF THE CIRCUMFERENCE WITH INCREASING GAS VELOCITY. THE MEAN LARGE WAVE HEIGHT AT THE PIPE BOTTOM IS LINEARLY RELATED TO THE LOCAL RMS VALUE. IT IS ALSO A STRONG FUNCTION OF GAS FLOW RATE, WITH A MODERATE DEPENDENCE ON LIQUID FLOW RATE. HOWEVER, THE DISTURBANCE WAVE INTERMITTENCY APPEARS TO BE ALMOST INDEPENDENT OF GAS AS WELL AS LIQUID FLOW RATES. (SHORTENED)","abstract_html":"TIME RECORDS HAVE BEEN COLLECTED OF LOCAL LIQUID FILM THICKNESS, USING PARALLELWIRE CONDUCTANCE PROBES, IN A NEW 50.8 MM I.D. PIPE LOOP. STATISTICAL ANALYSISOF THESE RECORDS ALLOWS THE STUDY OF CIRCUMFERENTIAL VARIATION OF TIME-AVERAGED THICKNESS AND OF OTHER QUANTITIES. THE POWER SPECTRA SHOW THAT THE DOMINANT FREQUENCY ASSOCIATED WITH LARGE WAVES IS &lt;10 HZ AT LOW GAS VELOCITIES, DISPLAYING A TENDENCY TO INCREASE WITH GAS FLOW RATE. BY COMBINING SIGNAL CROSS-CORRELATION DATA WITH VISUAL OBSERVATIONS, IT IS SHOWN THAT THE DISTURBANCE WAVES TEND TO DEFORM RAPIDLY, MOVE ON A PLANE INCLINED WITH RESPECT TO THE VERTICAL, AND COVER AN INCREASINGLY LARGER PORTION OF THE CIRCUMFERENCE WITH INCREASING GAS VELOCITY. THE MEAN LARGE WAVE HEIGHT AT THE PIPE BOTTOM IS LINEARLY RELATED TO THE LOCAL RMS VALUE. IT IS ALSO A STRONG FUNCTION OF GAS FLOW RATE, WITH A MODERATE DEPENDENCE ON LIQUID FLOW RATE. HOWEVER, THE DISTURBANCE WAVE INTERMITTENCY APPEARS TO BE ALMOST INDEPENDENT OF GAS AS WELL AS LIQUID FLOW RATES. (SHORTENED)","abstract_has_math":false,"creators":["Παράς, Σπυρίδων","Paras, Spyridon"],"institution":"Aristotle University Of Thessaloniki (AUTH)","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1991,"date_issued":"1991","date_published":"1991","updated_at":"2026-07-24T02:25:05Z","subjects":["LDA (ΑΝΕΜΟΜΕΤΡΙΑ LASER DOPPLAR)","ΔΑΚΤΥΛΙΟΕΙΔΗΣ ΡΟΗ","Ροές","ΚΑΤΑΝΟΜΗ ΣΤΑΓΟΝΙΔΙΩΝ","ΚΥΜΑΤΑ ΔΙΑΤΑΡΑΧΗΣ","ΛΕΠΤΕΣ ΣΤΟΙΒΑΔΕΣ","ΡΟΗ ΥΓΡΟΥ/ΑΕΡΙΟΥ","ΡΥΘΜΟΣ ΕΝΑΠΟΘΕΣΗΣ","ΣΥΜΠΑΡΑΣΥΡΜΟΣ","ΤΟΠΙΚΕΣ ΤΑΧΥΤΗΤΕΣ","ANNULAR FLOW","DEPOSITION RATES","DISTURBANCE WAVES","DROPLET DISTRIBUTION","ENTRAINMENT","FILM PROPERTIES","GAS-LIQUID FLOW","LDA","LOCAL VELOCITY","Thin films","Επιστήμες Μηχανικού και Τεχνολογία","Επιστήμη Χημικού Μηχανικού","Engineering and Technology","Chemical Engineering"],"languages":["gre"],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["10.12681/eadd/1708"],"render_values":[{"text":"10.12681/eadd/1708","href":"https://doi.org/10.12681/eadd/1708","code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10442/hedi/1708","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Παράς, Σπυρίδων","Paras, Spyridon"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["1991"]},{"key":"dc:publisher","label":"Institution","values":["Aristotle University Of Thessaloniki (AUTH)","Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης (ΑΠΘ)"]},{"key":"dc:type","label":"Dc Type","values":["PhD Thesis"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["LDA (ΑΝΕΜΟΜΕΤΡΙΑ LASER DOPPLAR)","ΔΑΚΤΥΛΙΟΕΙΔΗΣ ΡΟΗ","Ροές","ΚΑΤΑΝΟΜΗ ΣΤΑΓΟΝΙΔΙΩΝ","ΚΥΜΑΤΑ ΔΙΑΤΑΡΑΧΗΣ","ΛΕΠΤΕΣ ΣΤΟΙΒΑΔΕΣ","ΡΟΗ ΥΓΡΟΥ/ΑΕΡΙΟΥ","ΡΥΘΜΟΣ ΕΝΑΠΟΘΕΣΗΣ","ΣΥΜΠΑΡΑΣΥΡΜΟΣ","ΤΟΠΙΚΕΣ ΤΑΧΥΤΗΤΕΣ","ANNULAR FLOW","DEPOSITION RATES","DISTURBANCE WAVES","DROPLET DISTRIBUTION","ENTRAINMENT","FILM PROPERTIES","GAS-LIQUID FLOW","LDA","LOCAL VELOCITY","Thin films","Επιστήμες Μηχανικού και Τεχνολογία","Επιστήμη Χημικού Μηχανικού","Engineering and Technology","Chemical Engineering"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["gre"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["10.12681/eadd/1708","http://hdl.handle.net/10442/hedi/1708"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["TIME RECORDS HAVE BEEN COLLECTED OF LOCAL LIQUID FILM THICKNESS, USING PARALLELWIRE CONDUCTANCE PROBES, IN A NEW 50.8 MM I.D. PIPE LOOP. STATISTICAL ANALYSISOF THESE RECORDS ALLOWS THE STUDY OF CIRCUMFERENTIAL VARIATION OF TIME-AVERAGED THICKNESS AND OF OTHER QUANTITIES. THE POWER SPECTRA SHOW THAT THE DOMINANT FREQUENCY ASSOCIATED WITH LARGE WAVES IS <10 HZ AT LOW GAS VELOCITIES, DISPLAYING A TENDENCY TO INCREASE WITH GAS FLOW RATE. BY COMBINING SIGNAL CROSS-CORRELATION DATA WITH VISUAL OBSERVATIONS, IT IS SHOWN THAT THE DISTURBANCE WAVES TEND TO DEFORM RAPIDLY, MOVE ON A PLANE INCLINED WITH RESPECT TO THE VERTICAL, AND COVER AN INCREASINGLY LARGER PORTION OF THE CIRCUMFERENCE WITH INCREASING GAS VELOCITY. THE MEAN LARGE WAVE HEIGHT AT THE PIPE BOTTOM IS LINEARLY RELATED TO THE LOCAL RMS VALUE. IT IS ALSO A STRONG FUNCTION OF GAS FLOW RATE, WITH A MODERATE DEPENDENCE ON LIQUID FLOW RATE. HOWEVER, THE DISTURBANCE WAVE INTERMITTENCY APPEARS TO BE ALMOST INDEPENDENT OF GAS AS WELL AS LIQUID FLOW RATES. (SHORTENED)","Η ΜΕΛΕΤΗ ΑΥΤΗ ΕΧΕΙ ΣΚΟΠΟ ΤΗΝ ΠΛΗΡΕΣΤΕΡΗ ΚΑΤΑΝΟΗΣΗ ΤΗΣ ΟΡΙΖΟΝΤΙΑΣ ΔΑΚΤΥΛΙΟΕΙΔΟΥΣΡΟΗΣ ΥΓΡΟΥ/ΑΕΡΙΟΥ. ΟΙ ΜΕΤΑΒΟΛΕΣ ΤΟΥ ΤΟΠΙΚΟΥ ΠΑΧΟΥΣ ΤΗΣ ΥΓΡΗΣ ΣΤΟΙΒΑΔΑΣ ΜΕΤΡΟΥΝΤΑΙ ΜΕ ΕΙΔΙΚΗ ΑΓΩΓΙΜΟΜΕΤΡΙΚΗ ΜΕΘΟΔΟ. Η ΣΤΑΤΙΣΤΙΚΗ ΛΥΣΗ ΤΩΝ ΔΕΔΟΜΕΝΩΝ ΕΠΙΤΡΕΠΕΙ ΤΗ ΜΕΛΕΤΗ ΤΗΣ ΠΕΡΙΦΕΡΕΙΑΚΗΣ ΜΕΤΑΒΟΛΗΣ ΤΟΥ ΜΕΣΟΥ ΠΑΧΟΥΣ ΚΑΙ ΤΗΣ ΕΝΤΑΣΗΣ ΤΩΝ ΔΙΑΤΑΡΑΧΩΝ ΤΗΣ ΔΙΕΠΙΦΑΝΕΙΑΣ ΥΓΡΟΥ/ΑΕΡΙΟΥ. ΤΑ ΦΑΣΜΑΤΑ ΣΥΧΝΟΤΗΤΩΝ ΔΕΙΧΝΟΥΝ ΟΤΙ Η ΧΑΡΑΚΤΗΡΙΣΤΙΚΗ ΣΥΧΝΟΤΗΤΑ ΤΩΝ ΚΥΜΑΤΩΝ ΔΙΑΤΑΡΑΧΗΣ ΑΥΞΑΝΕΤΑΙ ΚΥΡΙΩΣ ΜΕ ΤΗΝ ΠΑΡΟΧΗ ΤΗΣ ΑΕΡΙΑΣ ΦΑΣΗΣ. ΤΑ ΚΥΜΑΤΑ ΔΙΑΤΑΡΑΧΗΣ ΑΛΛΟΙΩΝΟΝΤΑΙ ΣΧΕΤΙΚΑ ΓΡΗΓΟΡΑ, ΚΙΝΟΥΜΕΝΑ ΣΕ ΕΝΑ ΕΠΙΠΕΔΟ ΚΕΚΛΙΜΕΝΟ ΩΣ ΠΡΟΣ ΤΗΝ ΚΑΤΑΚΟΡΥΦΟ. ΤΟ ΥΨΟΣ ΑΥΤΩΝ ΤΩΝ ΚΥΜΑΤΩΝ ΕΙΝΑΙ ΓΡΑΜΜΙΚΗ ΣΥΝΑΡΤΗΣΗ ΤΗΣ ΤΟΠΙΚΗΣ ΤΙΜΗΣ RMS ΤΟΥ ΠΑΧΟΥΣ ΤΗΣ ΥΓΡΗΣ ΣΤΟΙΒΑΔΑΣ ΚΑΙ ΕΞΑΡΤΑΤΑΙ ΕΝΤΟΝΑ ΑΠΟ ΤΗΝ ΠΑΡΟΧΗ ΤΟΥ ΑΕΡΙΟΥ. Η \"ΑΙΧΜΗΡΟΤΗΤΑ\" ΤΟΥΣ ΜΕΙΩΝΕΤΑΙ ΜΕ ΑΥΞΗΣΗΤΗΣ ΠΑΡΟΧΗΣ ΤΗΣ ΑΕΡΙΑΣ ΦΑΣΗΣ, ΕΝΩ Η \"ΔΙΑΛΕΙΨΗ\" ΤΟΥΣ, Ι, ΕΙΝΑΙ ΣΧΕΔΟΝ ΑΝΕΞΑΡΤΗΤΗ ΑΠΟ ΤΙΣ ΠΑΡΟΧΕΣ ΤΩΝ ΔΥΟ ΦΑΣΕΩΝ. (ΠΕΡΙΚΟΠΗ)"]},{"key":"dc:title","label":"Title","values":["ΜΕΛΕΤΗ ΔΑΚΤΥΛΙΟΕΙΔΟΥΣ ΔΙΦΑΣΙΚΗΣ ΡΟΗΣ ΣΕ ΟΡΙΖΟΝΤΙΟ ΑΓΩΓΟ","ANNULAR TWO PHASE FLOW IN HORIZONTAL PIPE"]}]}],"canonical_facts":{"dc:creator":["Παράς, Σπυρίδων","Paras, Spyridon"],"dc:date":["1991"],"dc:description":["TIME RECORDS HAVE BEEN COLLECTED OF LOCAL LIQUID FILM THICKNESS, USING PARALLELWIRE CONDUCTANCE PROBES, IN A NEW 50.8 MM I.D. PIPE LOOP. STATISTICAL ANALYSISOF THESE RECORDS ALLOWS THE STUDY OF CIRCUMFERENTIAL VARIATION OF TIME-AVERAGED THICKNESS AND OF OTHER QUANTITIES. THE POWER SPECTRA SHOW THAT THE DOMINANT FREQUENCY ASSOCIATED WITH LARGE WAVES IS <10 HZ AT LOW GAS VELOCITIES, DISPLAYING A TENDENCY TO INCREASE WITH GAS FLOW RATE. BY COMBINING SIGNAL CROSS-CORRELATION DATA WITH VISUAL OBSERVATIONS, IT IS SHOWN THAT THE DISTURBANCE WAVES TEND TO DEFORM RAPIDLY, MOVE ON A PLANE INCLINED WITH RESPECT TO THE VERTICAL, AND COVER AN INCREASINGLY LARGER PORTION OF THE CIRCUMFERENCE WITH INCREASING GAS VELOCITY. THE MEAN LARGE WAVE HEIGHT AT THE PIPE BOTTOM IS LINEARLY RELATED TO THE LOCAL RMS VALUE. IT IS ALSO A STRONG FUNCTION OF GAS FLOW RATE, WITH A MODERATE DEPENDENCE ON LIQUID FLOW RATE. HOWEVER, THE DISTURBANCE WAVE INTERMITTENCY APPEARS TO BE ALMOST INDEPENDENT OF GAS AS WELL AS LIQUID FLOW RATES. (SHORTENED)","Η ΜΕΛΕΤΗ ΑΥΤΗ ΕΧΕΙ ΣΚΟΠΟ ΤΗΝ ΠΛΗΡΕΣΤΕΡΗ ΚΑΤΑΝΟΗΣΗ ΤΗΣ ΟΡΙΖΟΝΤΙΑΣ ΔΑΚΤΥΛΙΟΕΙΔΟΥΣΡΟΗΣ ΥΓΡΟΥ/ΑΕΡΙΟΥ. ΟΙ ΜΕΤΑΒΟΛΕΣ ΤΟΥ ΤΟΠΙΚΟΥ ΠΑΧΟΥΣ ΤΗΣ ΥΓΡΗΣ ΣΤΟΙΒΑΔΑΣ ΜΕΤΡΟΥΝΤΑΙ ΜΕ ΕΙΔΙΚΗ ΑΓΩΓΙΜΟΜΕΤΡΙΚΗ ΜΕΘΟΔΟ. Η ΣΤΑΤΙΣΤΙΚΗ ΛΥΣΗ ΤΩΝ ΔΕΔΟΜΕΝΩΝ ΕΠΙΤΡΕΠΕΙ ΤΗ ΜΕΛΕΤΗ ΤΗΣ ΠΕΡΙΦΕΡΕΙΑΚΗΣ ΜΕΤΑΒΟΛΗΣ ΤΟΥ ΜΕΣΟΥ ΠΑΧΟΥΣ ΚΑΙ ΤΗΣ ΕΝΤΑΣΗΣ ΤΩΝ ΔΙΑΤΑΡΑΧΩΝ ΤΗΣ ΔΙΕΠΙΦΑΝΕΙΑΣ ΥΓΡΟΥ/ΑΕΡΙΟΥ. ΤΑ ΦΑΣΜΑΤΑ ΣΥΧΝΟΤΗΤΩΝ ΔΕΙΧΝΟΥΝ ΟΤΙ Η ΧΑΡΑΚΤΗΡΙΣΤΙΚΗ ΣΥΧΝΟΤΗΤΑ ΤΩΝ ΚΥΜΑΤΩΝ ΔΙΑΤΑΡΑΧΗΣ ΑΥΞΑΝΕΤΑΙ ΚΥΡΙΩΣ ΜΕ ΤΗΝ ΠΑΡΟΧΗ ΤΗΣ ΑΕΡΙΑΣ ΦΑΣΗΣ. ΤΑ ΚΥΜΑΤΑ ΔΙΑΤΑΡΑΧΗΣ ΑΛΛΟΙΩΝΟΝΤΑΙ ΣΧΕΤΙΚΑ ΓΡΗΓΟΡΑ, ΚΙΝΟΥΜΕΝΑ ΣΕ ΕΝΑ ΕΠΙΠΕΔΟ ΚΕΚΛΙΜΕΝΟ ΩΣ ΠΡΟΣ ΤΗΝ ΚΑΤΑΚΟΡΥΦΟ. ΤΟ ΥΨΟΣ ΑΥΤΩΝ ΤΩΝ ΚΥΜΑΤΩΝ ΕΙΝΑΙ ΓΡΑΜΜΙΚΗ ΣΥΝΑΡΤΗΣΗ ΤΗΣ ΤΟΠΙΚΗΣ ΤΙΜΗΣ RMS ΤΟΥ ΠΑΧΟΥΣ ΤΗΣ ΥΓΡΗΣ ΣΤΟΙΒΑΔΑΣ ΚΑΙ ΕΞΑΡΤΑΤΑΙ ΕΝΤΟΝΑ ΑΠΟ ΤΗΝ ΠΑΡΟΧΗ ΤΟΥ ΑΕΡΙΟΥ. Η \"ΑΙΧΜΗΡΟΤΗΤΑ\" ΤΟΥΣ ΜΕΙΩΝΕΤΑΙ ΜΕ ΑΥΞΗΣΗΤΗΣ ΠΑΡΟΧΗΣ ΤΗΣ ΑΕΡΙΑΣ ΦΑΣΗΣ, ΕΝΩ Η \"ΔΙΑΛΕΙΨΗ\" ΤΟΥΣ, Ι, ΕΙΝΑΙ ΣΧΕΔΟΝ ΑΝΕΞΑΡΤΗΤΗ ΑΠΟ ΤΙΣ ΠΑΡΟΧΕΣ ΤΩΝ ΔΥΟ ΦΑΣΕΩΝ. (ΠΕΡΙΚΟΠΗ)"],"dc:identifier":["10.12681/eadd/1708","http://hdl.handle.net/10442/hedi/1708"],"dc:language":["gre"],"dc:publisher":["Aristotle University Of Thessaloniki (AUTH)","Αριστοτέλειο Πανεπιστήμιο Θεσσαλονίκης (ΑΠΘ)"],"dc:subject":["LDA (ΑΝΕΜΟΜΕΤΡΙΑ LASER DOPPLAR)","ΔΑΚΤΥΛΙΟΕΙΔΗΣ ΡΟΗ","Ροές","ΚΑΤΑΝΟΜΗ ΣΤΑΓΟΝΙΔΙΩΝ","ΚΥΜΑΤΑ ΔΙΑΤΑΡΑΧΗΣ","ΛΕΠΤΕΣ ΣΤΟΙΒΑΔΕΣ","ΡΟΗ ΥΓΡΟΥ/ΑΕΡΙΟΥ","ΡΥΘΜΟΣ ΕΝΑΠΟΘΕΣΗΣ","ΣΥΜΠΑΡΑΣΥΡΜΟΣ","ΤΟΠΙΚΕΣ ΤΑΧΥΤΗΤΕΣ","ANNULAR FLOW","DEPOSITION RATES","DISTURBANCE WAVES","DROPLET DISTRIBUTION","ENTRAINMENT","FILM PROPERTIES","GAS-LIQUID FLOW","LDA","LOCAL VELOCITY","Thin films","Επιστήμες Μηχανικού και Τεχνολογία","Επιστήμη Χημικού Μηχανικού","Engineering and Technology","Chemical Engineering"],"dc:title":["ΜΕΛΕΤΗ ΔΑΚΤΥΛΙΟΕΙΔΟΥΣ ΔΙΦΑΣΙΚΗΣ ΡΟΗΣ ΣΕ ΟΡΙΖΟΝΤΙΟ ΑΓΩΓΟ","ANNULAR TWO PHASE FLOW IN HORIZONTAL PIPE"],"dc:type":["PhD Thesis"]},"updated_at":"2026-07-24T02:25:05Z"}