ABSTRACT
FIGURE 5 displays the critical point of stability for rt-type, one lump approximation in same condition as FIGURE 4. This shows that rttype approximation is failly longer in critical (permissible) pipe length m.1d more precise than Lor Reverse L-type one, even though the dividing ratio of admittance a is ordinal 0.5. In addition, order of equation is still unchanged from other two types because there are the capacitances of the valve and the cylinder in just front and rear sides of the pipe, respectively. In order to improve this accuracy of rt-type furthermore, the optimum dividing ratio a is determined so that, for example at the mass M = 17 kg, the critical pipe length for the lumped model coincides that for distributed one. a is 0.461 in this case, which of course differs according to the system conditions.
