Boundary-Layer Meteorology

, Volume 129, Issue 2, pp 269–287 | Cite as

The Effect of Surface Heating on Hill-Induced Flow Separation

  • Huw W. Lewis
  • Stephen D. Mobbs
  • Simon B. Vosper
  • Andy R. Brown
Original Paper


A series of two-dimensional mixing length model simulations of boundary-layer flow over idealised ridges of varying steepness are conducted to investigate the effect of surface heating on flow separation. The relatively simple numerical approach used permits characterisation of the influence of heating for a variety of initial conditions and parameter values. For steep terrain, increased surface heating is shown to enhance the strength and extent of hill-induced separation. For more moderate terrain, a critical heating strength is required for a given hill width and background flow speed before separation is initiated. Sensitivity tests show the results to be insensitive to model parameters or the choice of mixing length. The results are accounted for using a scaling analysis in terms of a non-dimensional stability parameter.


Boundary layer Convection Hills 


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Copyright information

© British Crown Copyright 2008, the Met Office, UK 2008

Authors and Affiliations

  • Huw W. Lewis
    • 1
    • 2
  • Stephen D. Mobbs
    • 1
  • Simon B. Vosper
    • 2
  • Andy R. Brown
    • 2
  1. 1.Institute for Atmospheric ScienceUniversity of LeedsLeedsUK
  2. 2.Met OfficeExeterUK

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