Mixing Velocity Gradient (G / Gt)
The Camp-Stein velocity gradient G = sqrt(P / (mu x V)) and the Gt product that set floc formation.
Example
You enter
- Power input w 300
- Basin volume (m³) 100
- Water temp c 10
- Detention time (s) 1200
You get
- G value 48
- Gt value 57492
Checked against published worked examples from: Camp & Stein / Ten States Standards.
Details, formula, and sources
ScopeRapid mix wants G of at least 750/s (Ten States), flocculation G 20-70/s. G depends on water temperature through viscosity -- cold water is more viscous, so the same paddle delivers a lower G in winter and can drop below the 20/s floor. Too high a G shears the floc apart.
Formula or tableG = sqrt(P / (mu x V)); Gt = G x detention_time; mu = water dynamic viscosity at the given temperature.
Source and editionCamp-Stein velocity gradient (Camp & Stein 1943), by name; Recommended Standards for Water Works (Ten States) 2022 4.2.3(b) for the rapid-mix minimum.
Free accessThe velocity-gradient relation is a public water-treatment result; the viscosity comes from a standard water-property table and the treatment-process design governs.
What governsEstimate. AHJ and licensed professional govern.
API field namespower_input_w, basin_volume_m3, water_temp_c, detention_time_s, g_value, gt_value
- Temperature-viscosity mu from a water-property table (0.001307 Pa-s at 10 C, 0.00089 at 25 C); cold water lowers Gwater properties
- Target bands rapid mix G >= 750/s (Ten States 4.2.3(b)); flocculation G 20-70/s and Gt 10^4-10^5 (textbook practice; Ten States sets no G band for flocculation)Recommended Standards for Water Works 2022 / water-treatment texts