Numerical Simulation of Steady Supersonic and Hypersonic Flows over Simple Bodies of Revolution. Aero Report 9902

This paper reports on numerical results for supersonic and hypersonic steady flows over axisymmetric blunt bodies. Two-dimensional compressible Navier- Stokes equations are solved using a high- resolution upwind Roe’s scheme. A modification to the boundary conditions and the implementation of Harten’s entropy fix is proposed to improve the robustness of the code, which is then tested on an axisymmetric spike, cone and cylinder at freestream Mach numbers of 2.21, 6.00 and 30.00

Far-field Boundary Conditions for Solutions to the Navier-Stokes Equations. Aerospace Engineering Departmental report no. 9324

The effect of reducing the extent of the computational domain for transonic lifting flow over an aerofoil in an unbounded domain is examined. A correction to the far field boundary conditions is developed based on a far field expansion of the linearized small-disturbance equation. Improved accuracy is demonstrated on smaller computational domains

Nickel hydrogen low Earth orbit test program update and status

The current status of nickel-hydrogen (NiH2) testing ongong at NWSC, Crane In, and The Aerospace Corporation, El Segundo, Ca are described. The objective of this testing is to develop a database for NiH2 battery use in Low Earth Orbit (LEO) and support applications in Medium Altitude Orbit (MAO). Individual pressure vessel-type cells are being tested. A minimum of 200 cells (3.5 in diameter and 4.5 in diameter) are included in the test, from four U.S. vendors. As of this date (Nov. 18, 1986) approximately 60 cells have completed preliminary testing (acceptance, characterization, and environmental testing) and have gone into life cycling

Solution of the Euler Equations in Three Dimensional Complex Geometries Using a Fully Unfactored Method. Aerospace Engineering Report 9907

An unfactored implicit time-marching method for the solution of the three dimensional Euler equations on multiblock curvilinear grids is presented. For robustness the convective terms are discretised using an upwind TVD scheme. The linear system arising from each implicit time step is solved using a Krylov subspace method with preconditioning based on an block incomplete lower-upper (BELU(O)) factorisation. Results are shown for the ONERA M6 wing, a wing/body configuration and the NLR-F5 wing with launcher and missile. It was found that the simulation cost is relatively independent of the number of blocks used and their orientation. Comparison is made with experiment where available and good agreement is obtained

Approximate Jacobians for the Solution of the Euler and Navier-Stokes Equations. G.U. Aero Report 9705

This paper describes a method for efficiently solving the steady-state Euler and Navier-Stokes equations. Robustness is achieved through the use of an upwind TVD scheme for discretising the convective terms. The approximate solution is advanced in time implicitly and the linear system arising at each implicit step is solved using a Conjugate Gradient type method. The main emphasis of this paper is on the use of Jacobian matrices associated with a simpler spatial discretisation. This leads to better conditioned linear systems. The resulting method has lower memory and CPU-time requirements when compared with the one using exact Jacobians

Solution of the Euler Unsteady Equations Using Deforming Grids. G.U. Aero Report 9704.

No abstract available

Banana root and soil health project - Australia

The banana plant forms an adventitious root system that is dependent on soil physical, chemical and biological properties to function efficiently. A pot experiment demonstrated that increasing soil compaction was able to significantly reduce the weight of banana roots and shoots. However, in the presence of Radopholus similis the effects of soil compaction were obscured, due to the significant reduction in root weight caused by the nematode. The use of a basic set of soil quality indicators that can be readily used by farmers, was linked to soil nematode indicators to determine relationships between soil properties. In a survey of banana fields in North Queensland, different diameter root classes were affected differently by changing soil properties. Banana roots greater than 5 mm diameter were positively correlated with aggregate stability and negatively correlated with soil bulk density. Banana roots less than 1 mm were positively correlated with electrical conductivity. Specific interactions between soil properties become apparent as crop production systems become more uniform. This allows farmers to prioritise management options to improve the most deficient soil health indicators. The addition of organic amendments is one possible method of correcting degrading soils. The use of amendments with high carbon contents, such as grass hay, banana trash and lucerne hay, were able to significantly suppress R. similis in the roots of banana plants relative to untreated soil. Due to banana production being located near environmentally sensitive areas there is an increasing need to monitor and modify soil management practices. However, this needs to be linked with a framework that allows the integration of all soil components with a system to allow continual improvement in soil management to allow banana production to have minimal impact on the surrounding environment