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Fig. 7.33
Current-gathering
effect in a conductive
inclusion
are shifted up or down (with small horizontal displacement). In the case of resistive
inclusion with
S
1
/
S
1
yx
-curves
are shifted down (the flow-around effect). In the case of conductive inclusion with
S
1
/
=
1
/
16 the
xy
-curves are shifted up, while the
S
1
yx
-curves are shifted up
(the current-gathering effect). The magnitude of the static shift depends on
a
=
16 the
xy
-curves are shifted down, while the
/
b
.
Consider, for instance, the
yx
-curve in the vicinity of the resistive inclusion. Its shift
reflecting the flow-around effect dramatically increases when
a
/
b
changes from 0.2
to 5 and then decreases and vanishes when
a
. This reminds
the behavior of a prudent pedestrian who turns around a short barrier but climbs
over a long barrier.
Asymptotic estimates derived from (7.122) show that galvanic distortions caused
by the flow-around and current-gathering effects attenuate at the distances
/
b
changes from 5 to
∞
⎧
⎨
S
1
S
1
for
xy
y
>>
ab
(
a
+
b
)(1
−
)
,
=
(7
.
129)
+
⎩
2(
a
b
)
S
1
S
1
yx
.
for
