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Constrained Hermite Tls For Mesh-Free Derivative Estimation Near And On Boundaries, Robert A. Mcdonald, Alejandro Ramos
Constrained Hermite Tls For Mesh-Free Derivative Estimation Near And On Boundaries, Robert A. Mcdonald, Alejandro Ramos
Robert A. McDonald
A Taylor series least-squares approach to estimating derivatives on scattered data is extended to include derivative observation or specification. This approach allows improved estimation of derivatives near boundaries as compared with the standard ghost node approach. It also enables a unique method of estimating derivatives in a surface using only surface data.
Mission Performance Considered As Point Performance In Aircraft Design, Robert A. Mcdonald
Mission Performance Considered As Point Performance In Aircraft Design, Robert A. Mcdonald
Robert A. McDonald
The cruise or loiter performance of an aircraft is intimately tied to its wing loading and its thrust-to-weight ratio. Paradoxically, mission performance is often not considered when these fundamental aircraft parameters are determined in conceptual design. In this paper, the traditional constraint diagram is extended to include contours of range or endurance parameter. These performance metrics represent the mission-performance capability of the aircraft without sizing the aircraft to a particular mission. This gives the designer an immediate and intuitive understanding of the tradeoff between the point and mission performance of the aircraft. The potential freedom for the designer to choose …
A Meshless Finite Difference Scheme For Compressible Potential Flows, Alejandro Ramos, Robert A. Mcdonald
A Meshless Finite Difference Scheme For Compressible Potential Flows, Alejandro Ramos, Robert A. Mcdonald
Robert A. McDonald
A meshless solution algorithm for the full potential equation has been developed by applying the principles of the Taylor Least Squares (TLS) method. This method allows for a PDE to be discretized on a local cloud of scattered nodes without the need of connectivity data. The process for discretizing the full potential equation within a meshless framework is outlined along with a novel Hermite TLS technique for enforcement of Neumann boundary conditions. Several two-dimensional test cases were solved that compare well with analytical and benchmark solutions. The first test case solved for the subcritical compressible flow over a circular cylinder …