{"created":"2021-03-01T06:44:16.425323+00:00","id":8800,"links":{},"metadata":{"_buckets":{"deposit":"cc0673d9-ff52-42d6-a61a-3972fd5494b9"},"_deposit":{"id":"8800","owners":[],"pid":{"revision_id":0,"type":"depid","value":"8800"},"status":"published"},"_oai":{"id":"oai:tsukuba.repo.nii.ac.jp:00008800","sets":["3:233:244"]},"author_link":["35967"],"item_12_biblio_info_6":{"attribute_name":"書誌情報","attribute_value_mlt":[{"bibliographicIssueDates":{"bibliographicIssueDate":"1994","bibliographicIssueDateType":"Issued"}}]},"item_12_date_granted_46":{"attribute_name":"学位授与年月日","attribute_value_mlt":[{"subitem_dategranted":"1994-03-25"}]},"item_12_degree_grantor_44":{"attribute_name":"学位授与大学","attribute_value_mlt":[{"subitem_degreegrantor":[{"subitem_degreegrantor_language":"ja","subitem_degreegrantor_name":"筑波大学"},{"subitem_degreegrantor_language":"en","subitem_degreegrantor_name":"University of Tsukuba"}],"subitem_degreegrantor_identifier":[{"subitem_degreegrantor_identifier_name":"12102","subitem_degreegrantor_identifier_scheme":"kakenhi"}]}]},"item_12_degree_name_43":{"attribute_name":"取得学位","attribute_value_mlt":[{"subitem_degreename":"博士（工学） "},{"subitem_degreename":"Doctor of Philosophy in Engineering"}]},"item_12_description_4":{"attribute_name":"抄録","attribute_value_mlt":[{"subitem_description":"A free surface Benard problem, in which a horizontal layer of fluid with a deformable free surface is considered to be situated on a hot rigid plate, is proposed to study equilibrium instability and convective bifurcation phenomena of natural convection heated from below with a free surface. This problem is formulated as a free boundary problem governed by Boussinesq equations. A numerical approach using a spectral method is proposed to solve the free boundary problems. To cope with unknown and moving boundary, fixed domain method is applied to transform free boundary domain into fixed boundary domain in which the collocation spectral method is used. Numerical results of several test problems indicatid that the free boundary problem calculated by spectral method is of much better precision than calculated by finite defference method. A Fourier-Chebyshev collocation spectral method is presented for numerical calculation of the free surface Benard problem. The two-dimensional periodic Boussinesq equations are directly simulated for numerical analysis of equilibrium instability and convective bifurcation phenomena in the free surface Benard problem of a specific fluid in a specific geometric region. In comparison with the free surface Bernard  problem, the rigid surface Benard problem, a typical Bernard problem in which a horizontal fluid bounded by two rigid plates is considered to be heated from below, is calculated as well. Numerical results have revealed that in the free surface Benard problem, there exists also a stationary(steady) bifurcation solution of convection rolls which are well-known in the rigid surface Benard probelm. The convection rolls are symmetry and sruface is flat in the rigid surface Benard Problem, whereas the convection rolls are asymmetry and surface is significantly curved in the free surface Benard problem to show  the effect of a deformable free surface and its surface tension. Moreover, the numerical experiments indicate that there also exits a critical Rayleigh number in the free surface Benard probelm; when the Rayleigh number is smaller than the critical Rayleigh number, there is only a static solution; when the Rayleigh number is larger than the critical Rayleigh number, there occurs a bifurcation of convection rolls. The critical Rayleigh number has been investigated by numerical experiments and results show that the value of the critical Rayleigh number for the free surface Benard problem is smaller than that for the rigid surface Benard probelm.This indicates that equilibrium is less stable when there is a free surface and that it is easier for the onset of convection rolls in the free surface Benard problem than in the rigid surface Benard problem. Furthermore, the free surface Benard problem is studied by a linear stability theory to support the results indecated by direct simulations. The linearized perturbance boundary value problem is derived. The eigenvalues are numerically calculated to investigate the critical Rayleigh number. The critical Rayleigh number in vestigated by the linear stability theory shows satisfactory agreement with the critical Rayleigh number investigated by direct numerical simulations.","subitem_description_language":"en","subitem_description_type":"Abstract"}]},"item_12_description_45":{"attribute_name":"学位授与年度","attribute_value_mlt":[{"subitem_description":"1993","subitem_description_type":"Other"}]},"item_12_dissertation_number_47":{"attribute_name":"報告番号","attribute_value_mlt":[{"subitem_dissertationnumber":"甲第1255号"}]},"item_12_relation_37":{"attribute_name":"関係URI","attribute_value_mlt":[{"subitem_relation_name":[{"subitem_relation_name_language":"ja","subitem_relation_name_text":"全文はOPACにあり"}],"subitem_relation_type":"hasFormat","subitem_relation_type_id":{"subitem_relation_type_id_text":"https://www.tulips.tsukuba.ac.jp/opac/volume/630947","subitem_relation_type_select":"URI"}}]},"item_access_right":{"attribute_name":"アクセス権","attribute_value_mlt":[{"subitem_access_right":"open access","subitem_access_right_uri":"http://purl.org/coar/access_right/c_abf2"}]},"item_creator":{"attribute_name":"著者","attribute_type":"creator","attribute_value_mlt":[{"creatorNames":[{"creatorName":"Zhou, Weidong","creatorNameLang":"en"},{"creatorName":"周, 偉東","creatorNameLang":"ja"}],"nameIdentifiers":[{"nameIdentifier":"35967","nameIdentifierScheme":"WEKO"}]}]},"item_files":{"attribute_name":"ファイル情報","attribute_type":"file","attribute_value_mlt":[{"accessrole":"open_date","date":[{"dateType":"Available","dateValue":"2013-12-18"}],"displaytype":"detail","filename":"A1255.pdf","filesize":[{"value":"93.8 kB"}],"format":"application/pdf","mimetype":"application/pdf","url":{"objectType":"abstract","url":"https://tsukuba.repo.nii.ac.jp/record/8800/files/A1255.pdf"},"version_id":"f9a34664-dc2f-4272-b9e6-09bf8d2fd6f2"}]},"item_language":{"attribute_name":"言語","attribute_value_mlt":[{"subitem_language":"jpn"}]},"item_resource_type":{"attribute_name":"資源タイプ","attribute_value_mlt":[{"resourcetype":"doctoral thesis","resourceuri":"http://purl.org/coar/resource_type/c_db06"}]},"item_title":"Numerical analysis of natural convection with a free surface using a spectral method","item_titles":{"attribute_name":"タイトル","attribute_value_mlt":[{"subitem_title":"Numerical analysis of natural convection with a free surface using a spectral method","subitem_title_language":"en"}]},"item_type_id":"12","owner":"1","path":["244"],"pubdate":{"attribute_name":"PubDate","attribute_value":"2007-07-25"},"publish_date":"2007-07-25","publish_status":"0","recid":"8800","relation_version_is_last":true,"title":["Numerical analysis of natural convection with a free surface using a spectral method"],"weko_creator_id":"1","weko_shared_id":-1},"updated":"2023-04-21T04:55:44.332811+00:00"}