Curvature coefficient, abbreviated as \(C_c\), also called coefficient of curvature, a dimensionless number, classifies a soil as well graded or poorly graded. It is a measure of the fineness or coarseness of the soil particles. Particle size distribution curves are commonly used in geotechnical engineering to describe the distribution of different sizes of particles in a soil sample. These curves provide information about the proportion of various particle sizes within the soil.
Curvature Coefficient Categorizes Fluids into Different Regimes
- Mildly Curved Flow (C < 1) - The curvature effects are relatively small, and the flow behaves similarly to that in a straight channel.
- Moderately Curved Flow (1 < C < 100) - The curvature starts to significantly influence the flow patterns, leading to secondary flow structures.
- Strongly Curved Flow (C > 100) - The curvature dominates the flow behavior, and the secondary flow patterns become even more pronounced.
Curvature Coefficient Formula |
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\( C_c \;=\; \dfrac{ D_{30}^2 }{ D_{60} \cdot D_{10} }\) (Curvature Coefficient) \( D_{30} \;=\; \sqrt{ C_c \cdot D_{60} \cdot D_{10} } \) \( D_{60} \;=\; \dfrac{ D_{30}^2 }{ C_c \cdot D_{10} }\) \( D_{10} \;=\; \dfrac{ D_{30}^2 }{ C_c \cdot D_{60} }\) |
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| Symbol | English | Metric |
| \( C_c \) = Curvature Coefficient | \(dimensionless\) | \(dimensionless\) |
| \( D_{30} \) = the sieve diameter (grain size) which there are 30% of particles go through. | \(in\) | \(mm\) |
| \( D_{60} \) = the sieve diameter (grain size) which there are 60% of particles go through. | \(in\) | \(mm\) |
| \( D_{10} \) = the sieve diameter (grain size) which there are 10% of particles go through. | \(in\) | \(mm\) |
