Mixing coefficients for longitudinal and vertical mixing in the near field of a surface pollutant discharge

Figures & data

Figure 1 Layout of experimental set-up

Figure 2 (a) Tracer injection sampler, (b) tracer collecting sampler

Figure 3 Typical observed width-averaged tracer concentration versus time (C–t) curves

Table 1 Hydraulic parameters and mixing coefficients

Sl. no.	d (m)	Q (m^3/s)	U (m/s)	R b (m)	S o	U * (m/s)	E y /dU *	E x /dU *	U 1 (m/s)	U 2 (m/s)	U 3 (m/s)
1	0.123	0.0195	0.437	0.092	9.17 × 10^−4	0.029	0.1280	54.47	0.378	0.446	0.455
2	0.155	0.0224	0.370	0.121	9.17 × 10^−4	0.033	0.1203	21.92	0.327	0.375	0.386
3	0.1785	0.0305	0.438	0.128	9.17 × 10^−4	0.034	0.9114	171.14	0.414	0.465	0.468
4	0.0895	0.0158	0.454	0.063	9.17 × 10^−4	0.024	0.1771	41.55	0.400	0.479	0.488
5	0.1645	0.0259	0.404	0.123	9.17 × 10^−4	0.033	0.0679	15.15	0.378	0.437	0.448
6	0.1005	0.0184	0.470	0.069	9.17 × 10^−4	0.025	0.0900	26.68	0.413	0.496	0.506
7	0.103	0.0198	0.492	0.068	9.17 × 10^−4	0.025	0.0617	14.20	0.364	0.420	0.428
8	0.124	0.0210	0.434	0.095	1.18 × 10^−3	0.033	0.0867	9.56	0.362	0.440	0.459
9	0.134	0.0263	0.504	0.095	1.18 × 10^−3	0.033	0.0532	7.53	0.442	0.516	0.527
10	0.145	0.0276	0.487	0.105	1.18 × 10^−3	0.034	0.0667	4.95	0.397	0.478	0.500
11	0.164	0.0318	0.498	0.117	1.18 × 10^−3	0.037	0.1364	44.72	0.405	0.486	0503
12	0.196	0.0394	0.515	0.137	1.18 × 10^−3	0.040	0.0958	16.67	0.475	0.530	0.536
13	0.15	0.0282	0.482	0.109	1.18 × 10^−3	0.035	0.1052	27.87	0.380	0.470	0.550
14	0.115	0.0263	0.587	0.087	2.00 × 10^−3	0.042	0.2490	35.20	0.495	0.590	0.602
15	0.15	0.0341	0.583	0.114	2.00 × 10^−3	0.048	0.1086	17.49	0.551	0.632	0.627
16	0.128	0.0258	0.517	0.096	1.47 × 10^−3	0.037	0.0514	4.35	0.479	0.563	0.577
17	0.147	0.0290	0.506	0.111	1.47 × 10^−3	0.040	0.0559	7.56	0.437	0.510	0.512
18	0.162	0.0318	0.503	0.123	1.47 × 10^−3	0.042	0.1280	54.47	0.461	0.522	0.526
19	0.184	0.0367	0.512	0.138	1.47 × 10^−3	0.045	0.1203	21.92	0.467	0.532	0.542
20	0.109	0.0235	0.554	0.078	1.47 × 10^−3	0.034	0.9114	171.14	0.548	0.630	0.620

Figure 4 Computational procedure for search of optimum mixing coefficients E _x and E _y

Figure 5 Comparison of E _y predicted by Eq. (2) with observed values

Figure 6 Determination of longitudinal mixing coefficient E _x (m²/s)

Figure 7 Input C–t curves used for sensitivity analysis of E _x and E _y

Figure 8 Effect of error in values of E _x on accuracy of predicted C–t curves

Figure 9 Effect of error in E _y on accuracy of predicted C–t curves