Differential Equations Preview

d(S)d(t)=k·y·B·SKm+S
d(B)d(t)=k·B·SKm+S
k=0.3
y=0.75
Km=0.000001
Boundaries
t(0)=0
S(0)=5
B(0)=0.05
t(f)=20

Program validated. Ready to Solve.
# Example 24 - Stiff ODE System
# Biological Reactors
# Verified Final Values: B=6.71667, S=0
# Ref.:Prob. 6.1 in Problem Solving in Chemical...

# Solution algorithm is explicitly set to stiff
#@ DEQ_SOLUTION_METHOD_INDEX = 3

d(S)/d(t) = -k * y * B * S / (Km + S)
d(B)/d(t) = k * B * S / (Km + S)
k = 0.3
y = .75
Km = 1.e-6
t(0) = 0
S(0) = 5
B(0) = 0.05
t(f) =20

Calculated values

  Variable ▲ Initial Minimal Maximal Final Value
1B0.050.056.7176.7166667
2S5-1.494e-245-9.427991e-31
3t002020
Chart 1
Chart

Data Table (134 records)


#tSB
1050.05
20.16254.99812650.05249789
30.263754.99691250.05411698
40.4156254.99502040.05663972
50.64343754.99201540.060646035
60.877210144.9887110.06505194
71.10680994.9852320.06969064
81.33256534.98156930.07457405
91.55459924.9777170.07971062
101.77303144.9736680.085108966
111.98797634.96941660.090777904
122.1995434.96495530.09672636
132.40783524.96027760.1029634
142.61295274.9553760.10949828
152.81498984.9502450.11634035
163.01403764.94487570.12349915
173.21018244.9392620.13098434
183.4035084.9333960.13880573
193.5940934.927270.1469733
203.78201444.9208770.15549713
213.96734484.91420940.1643875
224.15015464.9072590.1736548
234.3305114.90001770.18330956
244.50847864.8924780.1933625
254.684124.88463160.20382445
264.8574954.876470.21470639
275.02866034.86798520.22601946
285.1976724.8591690.23777494
295.36458354.8500120.24998426
305.52944564.84050560.262659
315.6923084.83064170.27581087
325.85321864.8204110.28945172
336.01222324.8098050.3035936
346.1693674.79881330.31824866
356.3246924.7874280.3334292
366.478244.7756390.34914765
376.6300514.76343730.36541665
386.7801644.75081350.38224894
396.9286164.73775670.39965743
407.07544374.7242590.4176551
417.22068174.71030860.4362552
427.3643644.69589660.455471
437.5065244.6810130.47531608
447.64719254.6656470.49580398
457.78640174.64978840.5169485
467.924184.6334270.53876364
478.0605574.61655240.5612633
488.1955624.59915350.5844618
498.3292214.58121970.6083735
508.461564.56274030.63301295
518.5926074.5437040.65839475
528.72238354.52410.6845337
538.8509174.50391630.7114448
548.97822954.4831430.7391431
559.1043434.4617670.7676438
569.2292824.43977830.7969624
579.3530674.41716430.8271144
589.4757194.39391330.85811543
599.59725954.3700140.8899814
609.7177074.34545370.9227282
619.8370814.3202210.956372
629.9554014.2943030.9909291
6310.0726854.26768831.026416
6410.1889514.2403631.0628489
6510.3042184.21231651.100245
6610.4185014.1835341.1386209
6710.5318174.1540051.1779935
6810.6441834.1237151.2183803
6910.7556144.09265141.2597984
7010.8661264.0608011.302265
7110.9757334.02815151.3457981
7211.0844513.99468851.3904154
7311.1922933.96039921.4361346
7411.2992733.92526961.4829738
7511.4054063.88928651.5309513
7611.5107043.85243631.580085
7711.6151813.81470441.630394
7811.7188493.77607751.6818966
7911.821723.73654151.7346115
8011.9238083.69608161.7885578
8112.0251233.6546841.8437544
8212.1256763.61233451.9002208
8312.225483.5690181.957976
8412.3245463.52472022.0170398
8512.5205043.43312172.1391711
8612.6174173.3857912.2022786
8712.7136353.33741952.2667742
8812.8091663.28799152.3326778
8912.9040193.23749232.4000103
9012.9982053.18590622.4687917
9113.0917343.13321762.5390432
9213.1846123.07941132.610785
9313.2768523.0244712.6840386
9413.3684592.96838142.7588248
9513.4594432.91112612.835165
9613.5498132.85268932.913081
9713.6395782.79305482.9925935
9813.8173192.67012743.1564968
9913.9053132.60680153.2409313
10013.992732.5422123.3270504
10114.0795812.47634243.414877
10214.1658722.40917563.5044327
10314.2516092.3406953.5957403
10414.4214542.19972253.7837033
10514.5055742.12719683.8804045
10614.589172.0532883.9789493
10714.6722451.97797884.0793614
10814.7548071.90125184.1816645
10914.9184211.74347224.392037
11014.9994821.66238464.500154
11115.0800551.5798074.610257
11215.1601471.4957224.7223706
11315.3189041.3229564.9527254
11415.397581.23423865.0710154
11515.4757971.14394015.191413
11615.6308690.95852595.438632
11715.7077340.86337385.5655017
11815.7841590.76656745.6945767
11915.8601460.668088565.825882
12016.010810.466061566.095251
12116.085480.36250376.2333283
12216.2331750.150704126.515728
12316.2843650.075080626.616559
12416.370007-1.4941694e-246.7166667
12516.514563-1.8464385e-266.7166667
12616.604631-6.1577643e-276.7166667
12716.739735-2.053659e-276.7166667
12816.942389-6.8492795e-286.7166667
12917.24637-2.2843835e-286.7166667
13017.702343-7.619005e-296.7166667
13118.369009-2.5411517e-296.7166667
13219.035677-8.475454e-306.7166667
13319.702343-2.8268017e-306.7166667
13420-9.427991e-316.7166667
Raw data presented with 134 records.

Constant Values

ConstantkyKm
Value0.30.750.000001

Settings and Hints

 Name/SourceValueType
1 Total number of equations 5 Setting
2 Number of differential equations 2 Setting
3 Number of explicit equations 3 Setting
4 Reporting digits 10 Setting
5 Minimal License Free - 2 Setting
6 Elapsed time 0.733 ms Setting
7 Solution method stiff Setting
8 Independent variable accuracy. eps 0.00001 Setting
9 First stepsize guess. h1 0.02 Setting
10 Minimum allowed stepsize. hmin 2e-7 Setting
11 Good steps 167 Setting
12 Bad steps 16 Setting
13 Calculated Intermediate data points 50 Setting
14 Version 7.0.73 Setting
15 #@chart_size = 428,300 Default (array2)
16 #@chart_interpolate = 2 Default (integer)
17 #@chart_curve_width = 2 Default (integer)
18 #@report_fix_digits = 8 Default (integer)
19 #@report_show_charts = true Default (boolean)
20 #@report_show_data_points = true Default (boolean)
21 #@report_show_intermediate_data_points = true Default (boolean)
22 #@report_show_source = true Default (boolean)
23 #@report_show_header = false Default (boolean)
24 #@report_show_settings = true Default (boolean)
25 #@chart_all_curves = false Default (boolean)
26 #@chart_curves_stiff_grouping_percent = 50 Default (integer)
27 #@chart_y_curves = Default (array2)
28 #@chart_log_scales = 000 Default (string)
29 #@DEQ_SOLUTION_METHOD_INDEX = 3 Hint

Messages

 SeverityDescription
1Info-Infor- Differential variables (2) ; S, B
2Info-Infor- Explicit variables (3) ; k, y, Km
3Info-Infor- Independent variable = t

Source

# Example 24 - Stiff ODE System
# Biological Reactors
# Verified Final Values: B=6.71667, S=0
# Ref.:Prob. 6.1 in Problem Solving in Chemical...

# Solution algorithm is explicitly set to stiff
#@ DEQ_SOLUTION_METHOD_INDEX = 3

d(S)/d(t) = -k * y * B * S / (Km + S)
d(B)/d(t) = k * B * S / (Km + S)
k = 0.3
y = .75
Km = 1.e-6
t(0) = 0
S(0) = 5
B(0) = 0.05
t(f) =20