Browsing by Author "Duncan, W. J."

Browsing by Author "Duncan, W. J."

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  • Assessment of errors in approximate solutions of differential equations 
    Duncan, W. J. (College of Aeronautics, Cranfield, 1947-12)
    The term assessment is applied to any process which enables us to set rigid bounds to the error or to estimate its value. It is shown that upper and lower bounds can be assigned whenever the Green's function of the problem ...
  • The characteristics of systems which are nearly in a state of neutral static stability 
    Duncan, W. J. (College of Aeronautics, Cranfield, 1950-01)
    It is shown that the rate of subsidence or divergence ﮑ of a system which is near a state of neutral static stability can easily be calculated for knowledge of the mode of displacement in the neutral state and this model ...
  • Flutter of systems with many freedoms 
    Duncan, W. J. (College of Aeronautics, Cranfield, 1948-08)
    Experience has shown that it is often necessary to retain many degrees of freedom in order to calculate critical flutter speeds reliably, but this entails much labour. Part 1 discusses the choice of a minimum set of freedoms ...
  • Ignoration of distortional co-ordinates in the theory of stability and control 
    Duncan, W. J. (College of Aeronautics, 1946-12)
    Gates and Lyon have proposed to treat theoretically the stability and control of deformable aircraft by a method in which the distortion co-ordinates are ignored and the influence of distortion is allowed for by suitable ...
  • Some related oscillation problems 
    Duncan, W. J. (College of Aeronautics, Cranfield, 1949-04)
    Two simple means for establishing a relation between a pair of oscillation problems are briefly discussed. In the first, the displacements are connected by use of a differential operator. The set of natural frequencies is ...
  • Technique of the step-by-step integration of ordinary differential equations 
    Duncan, W. J. (College of Aeronautics, Cranfield, 1947-02)
    In Part 1 step-by-step methods are examined critically and emphasis is placed on the dependence of the error on the number n of steps used for a given range of the independent variable. The index of a process is defined ...