dorsal/arxiv
View SchemaAbsense of slow transients, and the effect of imperfect vertical alignment, in turbulent Rayleigh-Benard convection
| Authors | Guenter Ahlers, Eric Brown, Alexei Nikolaenko |
|---|---|
| Categories | |
| ArXiv ID | physics/0506034 |
| URL | https://arxiv.org/abs/physics/0506034 |
| DOI | 10.1017/S0022112006009888 |
Abstract
We report experimental results for the influence of a tilt angle beta relative to gravity on turbulent Rayleigh-Benard convection of cylindrical samples. The measurements were made at Rayleigh numbers R up to 10^11 with two samples of height L equal to the diameter D (aspect ratio Gamma = D/L = 1). The fluid was water with a Prandtl number sigma = 4.38. In contrast to the experiences reported by Chilla et. al. (2004) for a similar sample but with Gamma = 0.5 (D = 0.5 and L = 1.0 m), we found no long relaxation times. For R = 9.4 times 10^10 we measured the Nusselt number N as a function of tilt angle beta and obtained a small beta dependence about a factor of 50 smaller than the result found by Chilla et. al. (2004) for their Gamma = 0.5 sample. We measured side-wall temperatures at eight equally spaced azimuthal locations on the horizontal mid-plane of the sample and used their cross-correlation functions to find the turn-over time of the large-scale circulation (LSC). The resulting Reynolds numbers R_e^cc were found to increase with beta. An important conclusion is that the increase of R_e^cc with beta of the LSC does not significantly influence the heat transport. Over the range 10^9 < R < 10^11 the enhancement of R_e^cc at constant beta due to the tilt could be described by a power law of R with an exponent of -1/6, consistent with a simple model that balances the additional buoyancy due to the tilt angle by the shear stress across the boundary layers. Even a small tilt angle dramatically suppressed the azimuthal meandering and the sudden reorientations characteristic of the LSC in a sample with beta = 0. The azimuthal mean of the temperature at the horizontal mid-plane within our resolution was independent of beta.
{
"annotation_id": "6fb7cd2b-49d3-4bc2-8b44-78573608e61c",
"date_created": "2026-03-02T18:01:00.579000Z",
"date_modified": "2026-03-02T18:01:00.579000Z",
"file_hash": "a781d45d077b1edf8cac2d42b97f90d49877bfc13eb7d6aa7bf99157396f9a2a",
"private": false,
"record": {
"abstract": "We report experimental results for the influence of a tilt angle beta\nrelative to gravity on turbulent Rayleigh-Benard convection of cylindrical\nsamples. The measurements were made at Rayleigh numbers R up to 10^11 with two\nsamples of height L equal to the diameter D (aspect ratio Gamma = D/L = 1). The\nfluid was water with a Prandtl number sigma = 4.38. In contrast to the\nexperiences reported by Chilla et. al. (2004) for a similar sample but with\nGamma = 0.5 (D = 0.5 and L = 1.0 m), we found no long relaxation times. For R =\n9.4 times 10^10 we measured the Nusselt number N as a function of tilt angle\nbeta and obtained a small beta dependence about a factor of 50 smaller than the\nresult found by Chilla et. al. (2004) for their Gamma = 0.5 sample. We measured\nside-wall temperatures at eight equally spaced azimuthal locations on the\nhorizontal mid-plane of the sample and used their cross-correlation functions\nto find the turn-over time of the large-scale circulation (LSC). The resulting\nReynolds numbers R_e^cc were found to increase with beta. An important\nconclusion is that the increase of R_e^cc with beta of the LSC does not\nsignificantly influence the heat transport. Over the range 10^9 \u003c R \u003c 10^11 the\nenhancement of R_e^cc at constant beta due to the tilt could be described by a\npower law of R with an exponent of -1/6, consistent with a simple model that\nbalances the additional buoyancy due to the tilt angle by the shear stress\nacross the boundary layers. Even a small tilt angle dramatically suppressed the\nazimuthal meandering and the sudden reorientations characteristic of the LSC in\na sample with beta = 0. The azimuthal mean of the temperature at the horizontal\nmid-plane within our resolution was independent of beta.",
"arxiv_id": "physics/0506034",
"authors": [
"Guenter Ahlers",
"Eric Brown",
"Alexei Nikolaenko"
],
"categories": [
"physics.flu-dyn"
],
"doi": "10.1017/S0022112006009888",
"title": "Absense of slow transients, and the effect of imperfect vertical alignment, in turbulent Rayleigh-Benard convection",
"url": "https://arxiv.org/abs/physics/0506034"
},
"schema_id": "dorsal/arxiv",
"source": {
"execution_id": "b8147df2-634f-4453-a552-5e08db16ae6f",
"id": "arXiv Dataset IDs",
"type": "Model",
"variant": "snapshot-2026-03-01",
"version": "0.1.0"
},
"user_id": 1000002
}