Strength and Stiffness: Design of Structural Foundations 1.0 Introduction
Strength and stiffness. The balance between these qualities forms the basis for any structural foundation. The general hull structure of a ship focuses on distributed pressures, like hydrostatic pressure of the ocean. But our ships also include many concentrated loads, like the pedestal of a crane or a main engine. The art of foundation... Class Societies Class societies are not perfect, but they are absolutely necessary. We need organizations to provide quality assurance on ships, whose primary motivation lies solely in the quality of the ship, and not with national interests. Despite this necessity, a class society works best when we remember that they are not perfect. Everyone... Free Surface Moment Without proper management, the shifting liquid in a ship’s tanks can create a lethal scenario. Free surface moment (FSM) is one of the most frequently misunderstood elements in ship operation. The deck officer that values their life wants to understand free surface moment. The physics behind it, and how it applies to... 5 Steps to (NOT) Build a Boat No matter what, building your own yacht will always require more than you anticipated. Before making the commitment to build your own boat, take time to seriously consider all the hidden costs and extra effort required. The best yacht for you is the one you can finish. Composite Materials Theoretically, composites promise strength several thousand times greater than steel. So why don’t we have composite materials everywhere? The practical design of composites severly limits their capabilities. Once you understand the practical limits, it provides a useful design guide for how to apply composites and maximize their advantages. Welcome to DMS! Welcome to Datawave Marine Solutions (DMS). This is a site about naval architecture, engineering as science, and the marine industry. This site embodies two important ideas of science New ideas are explored in a logical manner with hard evidence.
New information is shared freely for the benefit of the entire industry. The marine industry is one... Stability Test Theory What science could possibly link moving a few weights on deck with calculating the light ship weight? Armed with knowledge, we carefully exploit physics to achieve high quality science without the fancy equipment. Today I explain some of the theory behind the stability test. Practical Stability Test: Naval Architect's Guide Every naval architect learns the theory of how to perform a stability test. But a well executed stability test employs very little theory, and a great deal of practical experience. This guide imparts some of that hard earned experience to make your next stability test go well. Practical Stability Test: Chief Engineer's Guide A stability test requires extensive work to prepare the vessel. Where do you go to find that work list? This guide should give you some advanced warning of what to expect. It covers all the practical matters for a Chief Engineer to prepare for their next stability test. Practical Stability Test: Master's Guide Smooth stability tests require planning, and practicality. As the vessel Master, you want to prepare for this thing that completely disrupts vessel operations. But you are a busy person, and engineers are very long winded. Instead, this guide provides a brief overview, focusing on the major elements that concern you with a... Practical Stability Test: Owner's Guide What are the practical steps necessary to execute a stability test? How to avoid the pitfalls? Who do you call to arrange everything? This guide gives advice to the vessel owner on how to prepare for a stability test, from start to finish. Instead of theory, we focus on the logistics... When You Need a Stability Test Certain as the sea, ships will require stability tests at some point in their life. Or maybe not. This article discusses the different types of stability tests and when regulations require them. What is a Stability Test Stability tests do not arrive instantly after you order one. It takes time and planning, and you should expect extensive coordination with several different organizations. But the ultimate benefit justifies the expense: a ship with reliable stability performance. This article unravels some of the mystery behind a stability test and why... Weight Control Weight control is not sexy, but the consequences of ignoring it can be very scary. If we ignore weight control, we risk a potentially unusable ship. That is why proper weight control starts with the right attitude: understanding the risks and the necessity of a weight estimate. Underway Replenishment Naval architects work daily as systems integrators, but it’s difficult to point to any one system and show where this adds value. So today I want to review some T-AO UNREP equipment, and show how none of this is possible without systems integration. Which Engineer Ships evolved to require a combination of expertise from highly specialized disciplines. If you want a modern vessel, expect a modern team of experts. So let’s meet all the different roles and learn who it takes to create a modern ship. Ship Model Scaling The physics of model scaling make it impossible to perfectly convert between model scale and ship scale. Learn how to get around the scaling correlation problem and convert from model scale to ship scale measurements. Next Level Hydrodynamics Time for an upgrade! Far beyond the single purpose testing facility, the modern towing tank expanded into a Swiss Army knife of experiments. Armed with new gadgets and advanced capabilities. Time to see what new tricks the tank holds for us! The Ship Towing Tank It may look like a swimming pool, but towing tanks exist for a different purpose. Dragging models down the tank propelled the science of ship design forward across the years. These pools deliver critical measurements for ship hydrodynamics. Discover why we pay such a high price for a fundamental tool of ship... How to Cut the Bunker Bill: Preparing for IMO 2020 Ready or not, here it comes! No matter who you talk to, IMO 2020 promises to be a time of uncertain fuel prices. If fuel prices will go up, your fuel consumption needs to go down. Here are eight practical ways to reduce your fuel consumption. How to Design a Waterjet: Key Elements of Waterjets What makes a waterjet work? What is the difference between a good and bad waterjet? Waterjets may appear to be brutes of power, but they rely on delicately balanced design equations. Learn the common elements that go into all waterjets and discover the best practices that you should expect from any decent... Breakthrough Technology for Oil Spill Cleanup Extreme spill technology (EST) developed a new approach to oil recovery. It works on the ocean, simpler and more reliable. Want to learn more? Guts of CFD: Multiphase Modeling In computational fluid dynamics (CFD), we often need to model scenarios that involve more than one fluid. Volume of fluid modeling (VOF) expands the capabilities of CFD to allow limitless combinations of different fluids. The world of VOF encompasses everything from droplets of diesel spraying in cylinder all the way up to tsunami... Practical CFD Modeling: Mesh Deformation Mesh deformation is incredibly frustrating, complicated, unstable . . . and unavoidable if you want to incorporate body motions into CFD. Modeling body motion demands mesh deformation, changing the mesh on the fly, while using it to solve transport equations. As you might expect, that brings a host of new challenges. This... Practical CFD Modeling: Time Variation When we add the time domain, simulations change from modeling steady scenarios to unsteady, where boundary conditions change over time. Beyond the physics, modeling unsteady flow requires a few changes to the CFD solver. Inner iterations, timestep, Courant Number, and data management all enter into the strategy for the CFD engineer. Today... Practical CFD Modeling: Volume of Fluid Modeling Computational Fluid Dynamics (CFD) can model multiple fluids with the volume of fluid method. (VOF) The volume of fluid method opens new horizons for advanced modeling, which requires additional planning from the CFD engineer. Dive into the boundary conditions, meshing strategy, stability concerns, and more. Discover the world of VOF modeling. Practical CFD Modeling: Turbulence Turbulence demands modeling just like any other equation in computational fluid dynamics (CFD). As the CFD engineer, you need to describe boundary conditions for your turbulence equations. This article describes how to define boundary conditions for turbulence and provides typical values for normal simulations. Guts of CFD: Near Wall Effects Turbulence does tricky things near walls. Boundary layers and laminar sublayers compact interesting flow patterns into a very small space. Small it may be, but experience proved we cannot ignore it. The boundary layer forms on the body, which is our object of interest, arguably the most critical region. Turbulence is... Guts of CFD: Turbulence How we address turbulence is the defining feature of modern computational fluid dynamics (CFD). No modern computer has the power to directly compute the full details of turbulence (as of 2019). Instead, we make approximations and develop empirical models. What type of approximation, and which models should you select? Guts of CFD: CFD Linear Solution The heart of any CFD program is an extremely efficient linear algebra solver. But CFD equations are non-linear. How do we stretch the limits of linear algebra to accommodate non-linear CFD equations? How do we take the mathematics from one cell and apply them to millions of cells?