Behavior of weak axisymmetric fountain in homogeneous fluid with coexistent temperature and concentration effects

Abstract

The behavior of weak axisymmetric fountains in homogeneous fluid with coexistent temperature and concentration effects is studied numerically over 0.25 ≤ FrT ≤ 2.0, − 0.75 ≤ N ≤ 5.0, and 20 ≤ Re ≤ 300, where FrT is the Froude number defined with temperature only, N is the buoyancy ratio representing the relative contribution of concentration to density compared to that of temperature, and Re is the Reynolds number. For each FrT, the maximum fountain height, fountain upflow width, and whole fountain width reduce with increasing N, as the combined negative buoyancy from temperature and concentration becomes stronger, while as FrT becomes larger, they increase due to the reduced overall negative buoyancy. Re has strong effects on these parameters, with a larger Re value leading to increased values of these parameters. If the overall Froude number, Fr, which is defined with combined temperature and concentration, is used instead of FrT, the existing scaling relations for the maximum fountain height for weak axisymmetric fountains with density coming from temperature only, are also applicable for the weak axisymmetric fountains with density coming from both temperature and concentration, when Fr ≲ 2.0. The quantified correlations for the characteristic parameters under the combined effects of Re and Fr have also been obtained with the numerical results.

Keywords

• Weak axisymmetric fountain
• Maximum fountain height
• Fountain upflow width
• Whole fountain width
• Numerical simulation