Start Date

2-3-2011 1:30 PM

Description

The scope of this session includes ablation effects on surface roughness and surface roughness effects on ablation. Ablation involves blowing, and so we address blowing including combined roughness and blowing effects. The two distinct types of ablating material surface roughness are defined with examples: 1) roughness related to the material inhomogeneity, and 2) roughness induced by turbulent flow that appears to be unrelated to material inhomogeneties.

Existing approaches for modeling ablative material surface roughness and blowing effects are overviewed. These range from empirical “augmentation factor” correlations to high-fidelity simulations of flow-surface interactions using modern CFD techniques. For models requiring input of roughness morphology information (e.g., effective sand grain roughness height), potential experimental and analytical sources of this information, and associated challenges, will be discussed. With regard to all modeling approaches for predicting ablative material surface roughness and its effects, experimental strategies for generating data needed for model development and validation will be emphasized.

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Mar 2nd, 1:30 PM

Overview of Roughness and Blowing Effects in Flows Over Ablating Surfaces

The scope of this session includes ablation effects on surface roughness and surface roughness effects on ablation. Ablation involves blowing, and so we address blowing including combined roughness and blowing effects. The two distinct types of ablating material surface roughness are defined with examples: 1) roughness related to the material inhomogeneity, and 2) roughness induced by turbulent flow that appears to be unrelated to material inhomogeneties.

Existing approaches for modeling ablative material surface roughness and blowing effects are overviewed. These range from empirical “augmentation factor” correlations to high-fidelity simulations of flow-surface interactions using modern CFD techniques. For models requiring input of roughness morphology information (e.g., effective sand grain roughness height), potential experimental and analytical sources of this information, and associated challenges, will be discussed. With regard to all modeling approaches for predicting ablative material surface roughness and its effects, experimental strategies for generating data needed for model development and validation will be emphasized.