Experimental study of turbulent flow over permeable rough surfaces
Abstract
A variety of turbulent flows are over surface that are rough and permeable. Evolution, engineering design, manufacturing constraints and natural phenomena lead to rough and permeable boundaries in these porous surfaces (e.g. flow in heat exchangers, forest and urban canopies, bird feathers and river beds). The permeability and the roughness of a porous surface alters the turbulent boundary layer that develops over it and consequently the wake past an object with surface porosity. This entirely depends on the interaction between the external flow in the boundary layer over the roughness or the wake and the flow field within the porous media. Despite the wide ranging impact and relevance, there is a clear lack of fundamental understanding and the scaling laws that relate the properties of porous media to the features of external flow. This points to the clear need for a systematic fundamental study aimed at understanding the flow mechanisms and the relationship between the properties of porous substrates, the flow field within the porous media and the structure of turbulent flow over and past them. In this project, we use the synergy with an existing EPSRC funded research grant to advance our understanding of turbulent flows over permeable rough surfaces. The goal is to carry out complementary experiments and utilise the data to situate the flow over permeable surfaces in the same framework as flow over rough surfaces. This requires us to examine the validity of the some fundamental tenets (such as outer layer similarity and existence of equivalent sandgrain roughness). This will allow us to develop a physical framework to understand the predict turbulent flow over permeable rough surfaces.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Jan 14, 2022
- Source ID
- FA95501917022
Entities
People
- Bharathram Ganapathisubramani
Organizations
- Air Force Office of Scientific Research
- United States Air Force
- University of Southampton