TURBULENT DIFFUSION IN THE WAKE OF A BLUNTNOSED BODY AT HYPERSONIC SPEEDS
Abstract
The structure of the wake behind a blunt-nosed body at hypersonic speeds is described, and simplified representations of the outer and inner wakes are introduced. The boundary between these two regions is supposed to be a sharp front, and the growth of the inner wake depends only on the gradient and value of the enthalpy at this front. Two limiting cases of the behavior of the turbulent diffusivity are studied: (1) locally similar turbulence, in which the flow at each station behaves like a slice of a low speed self-similar turbulent wake, so that the diffusivity is proportional to the local momentum defect or drag contained in the inner wake; (2) frozen diffusivity, in which the turbulent diffusivity depends only on the initial value of the drag coefficient for the inner wake at the neck. Specific examples of the growth of the turbulent inner wake are calculated for comparison with measurements made in ballistic ranges. A typical reentry example is also computed at M = 22 and an altitude of 100,000 feet, in order to illustrate the behavior of the enthalpy distribution, and the behavior of the profiles of electron density in the wake in the two limiting cases of thermodynamic equilibrium and pure diffusion (zero recombination).
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 01, 1961
- Accession Number
- AD0600632
Entities
People
- Leslie Hromas
- Lester Lees