Transition and mixing in axisymmetric jets and vortex rings

A class of impulsively started, axisymmetric, laminar jets produced by a time dependent joint source of momentum are considered. These jets are different flows, each initially at rest in an unbounded fluid. The study is conducted at three levels of detail. First, a generalized set of analytic creeping flow solutions are derived with a method of flow classification. Second, from this set, three specific creeping flow solutions are studied in detail: the vortex ring, the round jet, and the ramp jet. This study involves derivation of vorticity, stream function, entrainment diagrams, and evolution of time lines through computer animation. From entrainment diagrams, critical points are derived and analyzed. The flow geometry is dictated by the properties and location of critical points which undergo bifurcation and topological transformation (a form of transition) with changing Reynolds number. Transition Reynolds numbers were calculated. A state space trajectory was derived describing the topological behavior of these critical points. This state space derivation yielded three states of motion which are universal for all axisymmetric jets. Third, the axisymmetric round jet is solved numerically using the unsteady laminar Navier Stokes equations. These equations were shown to be self similar for the round jet. Numerical calculations were performed up to a Reynolds number of 30 for a 60x60 point mesh. Animations generated from numerical solution showed each of the three states of motion for the round jet, including the Re = 30 case

Effect of tail-fin span on stability and control characteristics of a Canard-controlled missile at supersonic Mach numbers

An experimental wind-tunnel investigation was conducted at Mach numbers from 1.60 to 3.50 to obtain the longitudinal and lateral-directional aerodynamic characteristics of a circular, cruciform, canard-controlled missile with variations in tail-fin span. In addition, comparisons were made with the experimental aerodynamic characteristics using three missile aeroprediction programs: MISSILE1, MISSILE2, and NSWCDM. The results of the investigation indicate that for the test Mach number range, canard roll control at low angles of attack is feasible on tail-fin configurations with tail-to-canard span ratios of less than or equal to 0.75. The conards are effective pitch and yaw control devices on each tail-fin span configuration tested. Programs MISSILE1 and MISSILE2 provide very good predictions of longitudinal aerodynamic characteristics and fair predictions of lateral-directional aerodynamic characteristics at low angles of attack, with MISSILE2 predictions generally in better agreement with test data. Program NSWCDM provides good longitudinal and lateral-directional aerodynamic predictions that improve with increases in tail-tin span

Bead Making at Murano and Venice

Bead Making at Murano and Venice, by B. Harvey Carroll, Jr., is a rare eyewitness account of beadmaking in and around Venice, Italy, towards the end of the First World War and documents the technology of the time as well as what impact the war had on the industry. Carroll\u27s report takes us through the various steps in the production of drawn or tube beads and also provides a historical perspective of the industry. Although the report presents much useful information, we now know much more about most aspects of glass beadmaking and endnotes provide much additional information and clarification

Problem Areas Concerning Foreign Investment in U.S. Real Estate

Current problems related to foreign investment in real estate have a long and involved history. After a brief historical review, this per- spective will consider present limitations on alien ownership of real es- tate, inconveniences such as disclosure of ownership, and incidental administrative side effects which place the foreign investor in a differ- ent position than a U.S. investor

Problem Areas Concerning Foreign Investment in U.S. Real Estate

Current problems related to foreign investment in real estate have a long and involved history. After a brief historical review, this per- spective will consider present limitations on alien ownership of real es- tate, inconveniences such as disclosure of ownership, and incidental administrative side effects which place the foreign investor in a differ- ent position than a U.S. investor

The European Pine Shoot Moth (Rhyacionia buoliana Schiff.): With Special Reference to Its Occurrence in the Eli Whitney Forest

The European pine shoot moth has been recognized as a pest .in Europe for over a century. It was first discovered in the United States in 1914, since when it has become a serious enemy of red pine. The insect is becoming increasingly abundant in this country and is known to be present in Massachusetts, Rhode Island, Connecticut, New York, New Jersey, Pennsylvania, West Virginia, Illinois, Ohio, Michigan, possibly Florida, and in the provinces of Ontario and British .Columbia in Canada. Some fifteen species of pines susceptible to injury in varying degree have been reported as hosts .of this insect, including many of the more important timber trees of both Europe and North Anlerica. A brief morphological description of the more important external characters of all stages of the insect has been give

Design and assembly sequence analysis of option 3 for CETF reference space station

A design and assembly sequence was conducted on one option of the Dual Keel Space Station examined by a NASA Critical Evaluation Task Force to establish viability of several variations of that option. A goal of the study was to produce and analyze technical data to support Task Force decisions to either examine particular Option 3 variations in more depth or eliminate them from further consideration. An analysis of the phasing assembly showed that use of an Expendable Launch Vehicle in conjunction with the Space Transportation System (STS) can accelerate the buildup of the Station and ease the STS launch rate constraints. The study also showed that use of an Orbital Maneuvering Vehicle on the first flight can significantly benefit Station assembly and, by performing Station subsystem functions, can alleviate the need for operational control and reboost systems during the early flights. In addition to launch and assembly sequencing, the study assessed stability and control, and analyzed node-packaging options and the effects of keel removal on the structural dynamics of the Station. Results of these analyses are presented and discussed