{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/70624"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/70624","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"An Experimental Study of Single and Multiple Turbulent Buoyant Jets in Crossflow","abstract":"The phenomenon of turbulent, buoyant jets in crossflow is a fundamental fluid mechanics problem with many application areas, including jets discharged from natural and mechanical draft cooling towers. Buoyant jets have been studied for many years, and as a result there exists a large body of literature on this and other related topics. An extensive review of this literature showed that there was a need for an improved laboratory simulation technique and quantitative data on both single and multiple buoyant jets.","abstract_html":"The phenomenon of turbulent, buoyant jets in crossflow is a fundamental fluid mechanics problem with many application areas, including jets discharged from natural and mechanical draft cooling towers. Buoyant jets have been studied for many years, and as a result there exists a large body of literature on this and other related topics. An extensive review of this literature showed that there was a need for an improved laboratory simulation technique and quantitative data on both single and multiple buoyant jets.","abstract_has_math":false,"creators":["Leylek, Jim A."],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Aeronautical and Astronautical Engineering","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-12-15T23:55:52Z","date_published":"2014-12-15T23:55:52Z","updated_at":"2026-07-22T22:26:03Z","subjects":["Physics, Fluid and Plasma"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[{"key":"dc:identifier","label":"Identifier","values":["(UMI)AAI8422115"],"render_values":[{"text":"(UMI)AAI8422115","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/2142/70624","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Leylek, Jim A."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-12-15T23:55:52Z","10000-01-01","1984"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Aeronautical and Astronautical Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Physics, Fluid and Plasma"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/70624","(UMI)AAI8422115"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["The phenomenon of turbulent, buoyant jets in crossflow is a fundamental fluid mechanics problem with many application areas, including jets discharged from natural and mechanical draft cooling towers. Buoyant jets have been studied for many years, and as a result there exists a large body of literature on this and other related topics. An extensive review of this literature showed that there was a need for an improved laboratory simulation technique and quantitative data on both single and multiple buoyant jets.","A new buoyant jet simulation technique is developed which uses a vertically downward discharge of cold nitrogen gas into a wind tunnel with discharge temperature of the jet ranging between -30(DEGREES)C and -150(DEGREES)C. This technique is capable of simulating the puff-like nature of prototype cooling tower plumes as evidenced by flow visualization which is inherent in this method. A large body of data are reported for both single and multiple jets covering a wide range of parameters. Single jet data are obtained for discharge densimetric Frounde number F varying between 0.2 and 2.4 and crossflow-to-exit velocity ratio k varying between 0.2 and 11.7. The multiple jet data are reported for three angles of orientation (theta) with F values varying between 1.1 and 2.7 and k between 0.5 and 3.","The single jet results show that trajectory is very sensitive to k. The discharge densimetric Froude number also affects the trajectory but to a lesser extent. Temperature decay, on the other hand, is more sensitive to F than it is to k. An increase in k has the effect of lowering the trajectory of the jet. The isotherm downwind extension, which is a measure of effective jet mixing, increases with k for k less than the critical value k(,*). For k > k(,*) this trend reverses, indicating a more enhanced jet mixing. Physically, k(,*) indicates onset of jet/wake interaction. In highly buoyant jets, jet/wake interaction is prolonged until very high k.","The multiple jets show that the inline configuration ((theta) = 0 degrees) results in considerably high trajectory compared with the oblique and crossflow cases for all F and k combinations encountered in the experiments. The oblique case trajectories are consistently higher than crossflow trajectories for k k(,*) the oblique case exhibits by far the lowest trajectories. Two mechanisms are identified for having a key role in the behavior of multiple buoyant jets, these are: (a) jet shielding and (b) jet/wake interaction.","Made available in DSpace on 2014-12-15T23:55:52Z (GMT). No. of bitstreams: 1 8422115.pdf: 7296253 bytes, checksum: 2d89c01eca6642362ca559468fb72a5a (MD5) Previous issue date: 1984","Embargo set by: Seth Robbins for item 70790 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","270 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984."]},{"key":"dc:title","label":"Title","values":["An Experimental Study of Single and Multiple Turbulent Buoyant Jets in Crossflow"]}]}],"canonical_facts":{"dc:creator":["Leylek, Jim A."],"dc:date":["2014-12-15T23:55:52Z","10000-01-01","1984"],"dc:description":["The phenomenon of turbulent, buoyant jets in crossflow is a fundamental fluid mechanics problem with many application areas, including jets discharged from natural and mechanical draft cooling towers. Buoyant jets have been studied for many years, and as a result there exists a large body of literature on this and other related topics. An extensive review of this literature showed that there was a need for an improved laboratory simulation technique and quantitative data on both single and multiple buoyant jets.","A new buoyant jet simulation technique is developed which uses a vertically downward discharge of cold nitrogen gas into a wind tunnel with discharge temperature of the jet ranging between -30(DEGREES)C and -150(DEGREES)C. This technique is capable of simulating the puff-like nature of prototype cooling tower plumes as evidenced by flow visualization which is inherent in this method. A large body of data are reported for both single and multiple jets covering a wide range of parameters. Single jet data are obtained for discharge densimetric Frounde number F varying between 0.2 and 2.4 and crossflow-to-exit velocity ratio k varying between 0.2 and 11.7. The multiple jet data are reported for three angles of orientation (theta) with F values varying between 1.1 and 2.7 and k between 0.5 and 3.","The single jet results show that trajectory is very sensitive to k. The discharge densimetric Froude number also affects the trajectory but to a lesser extent. Temperature decay, on the other hand, is more sensitive to F than it is to k. An increase in k has the effect of lowering the trajectory of the jet. The isotherm downwind extension, which is a measure of effective jet mixing, increases with k for k less than the critical value k(,*). For k > k(,*) this trend reverses, indicating a more enhanced jet mixing. Physically, k(,*) indicates onset of jet/wake interaction. In highly buoyant jets, jet/wake interaction is prolonged until very high k.","The multiple jets show that the inline configuration ((theta) = 0 degrees) results in considerably high trajectory compared with the oblique and crossflow cases for all F and k combinations encountered in the experiments. The oblique case trajectories are consistently higher than crossflow trajectories for k k(,*) the oblique case exhibits by far the lowest trajectories. Two mechanisms are identified for having a key role in the behavior of multiple buoyant jets, these are: (a) jet shielding and (b) jet/wake interaction.","Made available in DSpace on 2014-12-15T23:55:52Z (GMT). No. of bitstreams: 1 8422115.pdf: 7296253 bytes, checksum: 2d89c01eca6642362ca559468fb72a5a (MD5) Previous issue date: 1984","Embargo set by: Seth Robbins for item 70790 Lift date: Forever Reason: Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","Restricted to the U of I community idenfinitely during batch ingest of legacy ETDs","U of I Only","270 p.","Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984."],"dc:identifier":["http://hdl.handle.net/2142/70624","(UMI)AAI8422115"],"dc:subject":["Physics, Fluid and Plasma"],"dc:title":["An Experimental Study of Single and Multiple Turbulent Buoyant Jets in Crossflow"],"dc:type":["text"],"thesis:degree_discipline":["Aeronautical and Astronautical Engineering"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:26:03Z"}