Abstract
Turbulent thermal convection driven by a temperature difference is omnipresent in nature and it plays an important role in numerous industrial applications. RayleighBénard convection (RBC) where a fluid layer in a cavity heated from below and cooled from above, is a classical model problem for the study of thermal convection. Another model problem is vertical convection (VC) where the fluid layer is heated/cooled at the sides. Both RBC and VC can be viewed as extreme cases of tilted convection where the tilt angle is 0° for RBC and 90° for VC.
This thesis studies the above three model problems for thermal convection, i.e. RayleighBénard convection (Part I), tilted convection (Part II), and vertical convection (Part III).
In Part I, we study nonOberbeckBoussinesq (NOB) effects either due to density maximum of cold water near 4℃ (Chap. 2) or due to large temperature differences (Chap. 3) in turbulent RBC. We also investigate multistability of convection roll states (Chap. 4) and metastability of the zonal flow (Chap. 5) in turbulent RBC.
In Part II, we focus on tilted convection. We report that tilting can promote flow reversals in a twodimensional convection cell with aspect ratio 2 (Chap. 6). The global flow organization and heat transport for twodimensional tilted convection with small aspect ratio 0.5 (Chap. 7) and large aspect ratios (Chap. 8) are also discussed. We further study NOB effects in threedimensional tilted convection in Chap. 9.
In Part III, we investigate vertical convection, and we particularly focus on NOB effects in twodimensional vertical convection in Chap. 10.
This thesis studies the above three model problems for thermal convection, i.e. RayleighBénard convection (Part I), tilted convection (Part II), and vertical convection (Part III).
In Part I, we study nonOberbeckBoussinesq (NOB) effects either due to density maximum of cold water near 4℃ (Chap. 2) or due to large temperature differences (Chap. 3) in turbulent RBC. We also investigate multistability of convection roll states (Chap. 4) and metastability of the zonal flow (Chap. 5) in turbulent RBC.
In Part II, we focus on tilted convection. We report that tilting can promote flow reversals in a twodimensional convection cell with aspect ratio 2 (Chap. 6). The global flow organization and heat transport for twodimensional tilted convection with small aspect ratio 0.5 (Chap. 7) and large aspect ratios (Chap. 8) are also discussed. We further study NOB effects in threedimensional tilted convection in Chap. 9.
In Part III, we investigate vertical convection, and we particularly focus on NOB effects in twodimensional vertical convection in Chap. 10.
Original language  English 

Qualification  Doctor of Philosophy 
Awarding Institution 

Supervisors/Advisors 

Award date  6 Nov 2020 
Place of Publication  Enschede 
Publisher  
Print ISBNs  9789036550857 
DOIs  
Publication status  Published  6 Nov 2020 