[Sponsors]
Home > Wiki > Skin friction coefficient

# Skin friction coefficient

### From CFD-Wiki

(Difference between revisions)
|         |                                                                                                        |         |                                                                             |
|---------|--------------------------------------------------------------------------------------------------------|---------|-----------------------------------------------------------------------------|
|         |                                                                                                        |         |                                                                             |
| Line 6: |                                                                                                        | Line 6: |                                                                             |
|         |                                                                                                        |         |                                                                             |
|         |                                                                                                        |         |                                                                             |
| -       | It is related to the momentum thickness as follows: <math>C_f \equiv 2\frac{\{d theta}}{\{d x}}</math> | +       | It is related to the momentum thickness as follows: C_f = 2(d theta)/ (d x) |
| -       |                                                                                                        | +       |                                                                             |
|         |                                                                                                        |         |                                                                             |
|         |                                                                                                        |         |                                                                             |

## Revision as of 17:45, 7 April 2008

The skin friction coefficient, $C_f$, is defined by:

$C_f \equiv \frac{\tau_w}{\frac{1}{2} \, \rho \, U_\infty^2}$

Where $\tau_w$ is the local wall shear stress, $\rho$ is the fluid density and $U_\infty$ is the free-stream velocity (usually taken ouside of the boundary layer or at the inlet).

It is related to the momentum thickness as follows: C_f = 2(d theta)/ (d x)

Someone should add some correlations and references for them here
{"extraction_info": {"found_math": true, "script_math_tex": 0, "script_math_asciimath": 0, "math_annotations": 0, "math_alttext": 0, "mathml": 0, "mathjax_tag": 0, "mathjax_inline_tex": 0, "mathjax_display_tex": 0, "mathjax_asciimath": 0, "img_math": 5, "codecogs_latex": 0, "wp_latex": 0, "mimetex.cgi": 0, "/images/math/codecogs": 0, "mathtex.cgi": 0}, "config": {"markdown_headings": true, "markdown_code": true, "boilerplate_config": {"ratio_threshold": 0.18, "absolute_threshold": 10, "end_threshold": 15, "enable": true}, "remove_buttons": true, "remove_image_figures": true, "remove_link_clusters": true, "table_config": {"min_rows": 2, "min_cols": 3, "format": "github"}, "remove_chinese": true, "remove_edit_buttons": true, "extract_latex": true}, "english_confidence": 0.8744864463806152, "perplexity_flag": "middle"}