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Dynamics of LSC in single layer FC77 RBC. Experimental setup. D. 3. 4. 2. 5. 1. 6. 8. 7. N. H=D. 1. E. 5. Inner Diameter D=2.5mm Outer Diameter D=10mm. 6. 8. 7. Level condition: E:0.0015 rad N:0.002 rad. 20mm. 0.7mm. Measurement Condition. Pr=19.4( T_center =40 o C)
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Experimental setup D 3 4 2 5 1 6 8 7 N H=D 1 E 5 Inner Diameter D=2.5mm Outer Diameter D=10mm 6 8 7 Level condition: E:0.0015 rad N:0.002 rad 20mm 0.7mm
Measurement Condition • Pr=19.4(T_center=40oC) • Ra=2.0*1011 • Aspect ratio=1 • Measurement period:29.05days (940774 run) • Method used: Multi-thermal probe method Analysis: TEE (Temperature Extreme Extraction) SF (Sinusoidal Fitting)
TEE and SF methods Q. Zhou, H.-D. Xi, S.-Q. Zhou C. Sun and K.-Q. Xia JFM 2009
Properties of the azimuthal temperature profile 3 4 2 NORTH 1 EAST 5 6 8 7
Cessation Frequency • Using the same criteria as Xi HD used, the cessation frequency of different layer is: A_threshold=0.3*<A>
HD Xi &KQ XIA 2006 PRE,73,056312 The cessation frequency is almost the same as that of single layer water RBC(the same aspect ratio). Thus the influence of Pr number on LSC is not strong. E.Brown &G. Ahlers, JFM,2006,568,pp351-386
Statistics of A and ϴ using the SF method
Different Flow Mode Cessation simultaneously
Different Flow Mode Reversal without cessation
Different Flow Mode SRM-DRM-SRM transition
Different Flow Mode From top to below: Phase during a cessation Amplitude during a cessation Complex flow mode during cessation Simultaneous cessation part (About 2 times the plume turn over time)
HD Xi PRL 2009 E.Brown JFM 2009
Sloshing and Twisting oscillation of the Large-scale circulation The motion of LSC in one cycle. t=0 t=1/4T t=1/2T t=3/4T
Power spectrum of temperature measured inside the sidewall(Top)
Power spectrum of temperature measured inside the sidewall(Middle)
Power spectrum of temperature measured inside the sidewall(Bottom)