Large-scale measurements and numerical simulations of in-cloud icing around a mountain ridge

Atmospheric icing by in-cloud icing has been measured around the ridge of Mt. Gaustatoppen (59°51', 08°N39'E) in Norway, during a period of 5 days. Sixteen sticks of 2 m height and 32 mm diameter were placed around the edge of the mountain ridge. The icing on the sticks was measured as well as the meteorological conditions. A finite volume CFD solver was used to simulate the wind flow and the rate of icing around the top 270 m of the mountain.Measurements and simulations show that even small variations in the location of the sticks around the ridge of a mountain peak, can cause large variations in accreted ice on the sticks. A basic understanding of the air flow around isolated mountain peaks is vital to understand how complex topography and altering wind direction strongly influence icing intensity. In this case use of a micro-scale numerical model to describe the wind field around the mountain peak, or measurements at the location for a short period of time, proves to give valuable information.

► Atmospheric icing on a mountain top was measured.
► Atmospheric icing was simulated using Computational Fluid Dynamics (CFD).
► The measurements were compared with numerical results.