1 / 12

Darcy s Law 1856

Units. Hydraulic Conductivity (K)

koto
Download Presentation

Darcy s Law 1856

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

    1. 1

    2. Units Hydraulic Conductivity (K)……[L/T] Specific Storage (S) ……. [1/L] Hydraulic Head Elevation (h) ……[L] Pressure head (P/?g) …….[L] Velocity head (v2/2g) ……[L] negligible 2

    3. 3

    4. 4 DARCY’S LAW q = Darcy flux or hydraulic flux (L/T) K = Saturated hydraulic conductivity (L/T) dH = difference in total head (L) dl = distance increment (L) dH/dl = I = hydraulic gradient (unitless)

    5. 5 Darcy’ Law

    6. 6 Darcy’ Law

    7. 7 DARCY’S LAW Q = total flow (L3/T) A = total cross-sectional area (L2) Q = qA

    8. 8 DARCY’S LAW Actual water velocity is higher than q and called the pore water velocity, v. v = q/n n = porosity

    9. 9 Example Consider measurements taken at two monitoring wells in an unconfined aquifer. The wells are located 200 m apart. The average K of the aquifer is 3.5 m/day. The observed values are 23.1 m and 24.2 m. Find the total flow across the aquifer and the transmissivity.

    10. 10

    11. 11 Example q = -K dh/dx Using consistent units of meters and days, h1 = 23.1, h2=24.2, K=3.5 q = -K . (h2-h1)/(x2-x1) = -3.5 . (24.2-23.1)/(200-0) = - 0.01925 m/day

    12. 12 Since q is negative, flow is opposite to the direction of x. This is correct because flow occurs from high potential to low potential. Q = qA = 0.01925 x 0.5(24.2+23.1)x1 = 0.455 m3/m-day T = KD D = 0.5(24.2+23.1) = 23.65 m T = 3.5x23.65 = 82.8 m2/day

    13. Deriving flow equations 13

More Related