Steady Definition and 231 Threads

Hi all, can i know is it true that charge flow is equal to zero at steady state current? Or is the rate of charge flow equal to zero. Thanks :)

Hey! When a stream is steady-state, you can cancel the acceleration term in navier-stokes equation, right? so: \rho \vec{a} = 0 = - \nabla P + \rho \vec{g} + \mu \nabla ^2 \vec{V} But there are many terms in the total acceleration which are not dependant on time! The acceleration term in...

Hello everyone, I have this setady state, heat transfer problem; I hope you can help me with it. I have flux source of 400 W/m² (a lamp), and i want to calculate the heat flux passing through a surface arbitrarily placed and oriented in the space. There is air in between. How can i do this...

Suppose I am putting a compound A in a reactor where the reaction A → B is occurring. If the concentration of A coming into the tank and leaving the tank are not changing (meaning, the value of C_a in is not the same as C_a out, but C_a out stays the same throughout) and the volumetric flow rate...

Homework Statement a) Determine the phasor current and impedance of the circuit b) Determine the steady-state current i(t). Homework Equations impedance conversion: ZL = ωLj ZC = -1j/ωC ZR = RPolar form conversion: rectangular form = R + jX Zmag = (j2 + r2)1/2 Zangle = arctan(j/r)V = IR...

Hello, I'm having trouble with a conduction problem, I have access to the answer but not the solution. I did it on my own and my value is half of what the answer is. Now, my calculus is a little rusty, but I don't know where I am going wrong. So the dimensions and temperatures of the sphere...

I'm having trouble solving this problem. I'm trying to find the steady state angle of a rod with wind /fluid drag. Assume Cd, L, U, etc. are known. The viscous and form drag forces are a function of the angle θ so I don't have enough equations to solve the problem. Maybe there's some type of...

Homework Statement A flat plate lies in the region: 0<x<35, 0<y<inf The temperature is steady (not changing with time), and the boundary conditions are: T = { x if 0<x<35; y=0 70-x if 35<x<70; y=0 0...

Homework Statement Subpart of the question requires me to find the steady state of the transition matrix: P=\begin{bmatrix} 0.1 & 0.7 & 0.2 \\ 0.1 & 0.8 & 0.1\\ 0.3 & 0.1 & 0.6 \end{bmatrix} Homework Equations We thus need to find vector \boldsymbol{v} in the equation...

Homework Statement Find the steady state temperature ##U(r, \theta)## in one-eighth of a circular ring shown below: Homework Equations The Attempt at a Solution I start by assuming a solution of the form ##u(r,\theta) = R(r)\Theta(\theta)##. I also note that ##u(r,\theta)##...

Nozzle: Why for subsonic flow the cross-sectional area of nozzle decreases?

Hi all, I am getting confused about how to calculate steady state error in a system. My particular transfer function is: G(s)= 4.992/(s^2+3s-1) Firstly, with an input step am I right in saying that the Steady State error will always be zero? If so can someone explain the reason behind this...

Hey, Can someone explain to me how you calculate time to steady rate? Or provide a website that explains it? Not having much luck :( Thanks!

Essentially, this looks like a differential equation problem but being rusty on differential equations I am a little stuck. Homework Statement Consider the following SDE d\sigma = a(\sigma,t)dt + b(\sigma,t)dW The Forward Equation (FKE) is given by \frac{\partial p}{\partial t} =...

I have attached the picture of the circuit. I'm trying to figure out the steady state voltages across the 2 resistors and the capacitor. V_s is given to be 10V DC. At steady state in a DC circuit, a capacitor acts as an open. When that happens, we shouldn't expect any current to flow...

Hi all I am doing a university module on vehicle dynamics and wish to clarify/enhance my understanding of vehicle handling and the effects of weight transfer. Here are a points based some past exam questions and my answers, if anyone can spot a mistake or would like to add anything this would...

Homework Statement I'm unable to solve a problem of heat equation in a cylinder in steady state. The problem is a cylinder of radius a and a height L. The boundary condition are ##T(\rho , \theta , 0)=\alpha \sin \theta##, ##T(\rho, \theta , L)=0## and ##\frac{\partial T}{\partial \rho} (a...

This is the problem: http://oi47.tinypic.com/6qij4o.jpg I set fx, fy, and B equal to zero. 'x' forces: Fx - Bsin(30) = 0 'y' forces: Fy - mg + B(cos(30)) = 0 lower end: -0.5*mg(cos(30)) + 0.4*B = 0 Using the third equation I solved for B, and got -477.4. I then plugged B into the...

Hi all, I am wondering how I plot the steady state temperature distribution of a square flat sheet in maple. I solved the initial partial differential equation I was given and ended up with a function generalized as T(x,y) =(constants)*sum(stuff). Which is a Fourier series representing...

Homework Statement Water is discharged from a reservoir through a pipe 700m long. For the first 100m of its length the pipe is 100mm in diameter and then suddenly enlarged to 150mm diameter for the remaining 600m. The pipe terminates in a nozzle which discharges a jet 25mm in diameter at a...

Hi, I'm interested in the theory of an Aluminum sphere that is initially at some temperature that is hotter than its surroundings. The sphere is surrounded by air at some small radius, say one meter, and then the air and sphere are both enclosed by an infinite shell of Aluminum at some...

I come from a civil engineering background and I'm about to start a masters in nuclear energy. I have no experience in thermodynamics and I've been doing a bit of revision before the course commences to get me up to speed. I've been working my way through 15 revision questions and I only have a...

(1) A mass of 3.0 kg is suspended from a vertical spring and produces a static deflection of 60 mm. The system is also subjected to viscous damping of 36 N s/m. Calculate the value of the: (a) natural frequency i. In Hz ii. And rad/s (b) damping ratio...

Homework Statement Air is to be compressed from 120 kPa and 310 K to 700 kPa and 430 K. A heat loss of 20 kj/kg occurs during the compression process. For air: cv=0.7165 kj/kg.K and R=0.287 kj/kg.K . A) Neglecting kinetic energy changes determine the power input required for a mass flow...

I have a project where I need to solve T''(x) = bT^4 ; 0<=x<=1 T(0) = 1 T'(1) = 0 using finite differences to generate a system of equations in Matlab and solve the system to find the solution So far I have: (using centred 2nd degree finite difference) T''(x) = (T(x+h) - 2T(x) +...

So would the inductance of a inductor be effected if it was in a large steady state magnetic field. Say the inductor produces a field of about .01 Tesla and the large electromagnet produces a field of 1 Tesla or more. How would a high permeable core vs a air core effect it? Would it add...

Homework Statement So this is a bit of a two-part question and I'm unsure which part I'm not doing right (or both!). i) Find the closed loop transfer function of the system shown ii) Design a proportional controller for the system to give a 10% steady state error Any help, hints, suggestions...

Homework Statement At steady state, a stream of liquid water at 20C, 1bar is mixed with a stream of ethylene glycol (M=62.07 g/mol) to form a refrigerant mixture that is 50% glycol by mass. The water molar flow rate is 4.2 kmol/min. The density of ethylene glycol is 1.115 times that of water...

http://dl.dropbox.com/u/33103477/2007%2010b.png I'm can't get my head around this question, there doesn't seem to be enough information to compute a steady state ? Any ideas on how to begin ??

http://dl.dropbox.com/u/33103477/harvesting.png So am I right in saying the 2 steady states are: N_1=\frac{h}{r}, N_2=\frac{1-h}{\alpha} Now plugging in N_1 into the equation I get: \frac{-h^2 \alpha}{r} < 0 So N_1 is stable. But I can't quite figure out how to classify...

http://dl.dropbox.com/u/33103477/model.png Form of the equation \gamma -\delta p_t = \frac{p_{t-1}-\alpha}{\beta} or p_t = \frac{-1}{\delta \beta}p_{t-1} + \frac{\alpha + \gamma \beta}{\delta \beta} So the steady state is p^* = \frac{\alpha + \gamma \beta}{\delta \beta + 1}...

Cubic Population Model with steady states ! I am unsure as what this question means: Consider the cubic population model: dN/dt = cN(N-k)(1-N) where c>0 and 0<k<1 If the the initial populations is N_0 describe without proof the future of the population, distinguish the various cases on...

Homework Statement Consider the steady flow between two long cylinders of radii R_1 and R_2, R_1 > R_1, rotating about their axes with angular velocities \Omega_1, \Omega_2. Look for a solution of the form, where \hat{\boldsymbol{\phi}} is a unit vector along the azimuthal direction...

A straight, uniform circular pipe of internal diameter of 88.43 mm and external diameter of 118.38 mm carries hot water at 63.67 deg cel. The pipe has a thermal conductivity of 247 Wm^-1 K^-1. how to calculate the steady-state rate of heat transfer per unit length, in W m^-1, when the outside...

Homework Statement Air passes over an electrical heater at a steady rate of 2500cm^3 per second. The inlet temperature of the air is 20^oC ( 20 degrees celcius ) and the steady outlet temperature is 40^0C ( 40 degrees celcius) a) What heat is absorbed by air passing over the heater in 2...

I know that in an AC circuit at the steady state a capacitor behaves like a short and inductor behaves like an open. Since the inductor is open wouldn't that just mean the answer is 0?

Hey all. I sure hope somebody can assist with this! I am a hobby beer brewer and am writing my own heat control algorithms. Part of the process involves heating water to a desired temperature setpoint. I'm using an electric water heater element (5500W) inside the water vessel (~5-10 gal)...

I am trying to understand steady state tracking error. I was looking over one of the example problems in my textbook and this is what it said: G(s) = (-1)/(100(s^2-10.791)) D(s) = K(s+5)/(s+10) Td(s) = 1/s as it states above I don't understand how they got the value 3300... I got 2156 when...

\begin{align} \dot{x} =& -x + ay + x^2y\notag\\ \dot{y} =& b - ay - x^2y\notag \end{align} The only steady states are $(-b,0)$ and $\left(0,\frac{b}{2a}\right)$, correct? I feel like there should be more but I don't think there any.

$N_{t + 1} =\begin{cases}rN_t^{1 - b}, & N_t > K\\ rN_t, & N_t < K \end{cases}$The steady states are when $N_{t + 1} = N_t = N_*$. $$ N_{*} =\begin{cases}rN_*^{1 - b}, & N_* > K\\ rN_*, & N_* < K \end{cases} $$ So the steady states are $N_* = \sqrt[b]{r}$ and $N_* = 0$. I am not sure how to...

So the book is showing an example about discrete steady states but neglected to show how the steady states were found. Here is what it has $u_{t+1}=ru_{t}(1-u_t), \quad r>0$ where we assume $0<r<1$ and we are interested in solutions $u_t>0$ Then it list the steady states $u^*=0, \quad...

Homework Statement Determine the equilibrium temperature distribution for a one-dimensional rod composed of two different materials in perfect thermal contact at x=1. For 0<x<1, there is one material (cp=1, K0=1) with a constant source (Q=1), whereas for the other 1<x<2 there are no sources...

I am facing a problem on transport phenomena. Can anyone help me to solve this problem. I would really appreciate it. Its little urgent. I know that i have to use shell mass balance to start the problem but how to proceed further is what making me confused. In a beaker, a solid sphere of...

I am trying to show that there are 3 nonzero steady states of \frac{du}{dt}=ru\left(1-\frac{u}{q}\right)-\left(1-\exp\left(-\frac{u^2}{\varepsilon}\right)\right)=0 I have tried using Mathematica and Mathematica couldn't solve it. I tried some algebra and that wasn't going anywhere so I am at a...

Steady states for a system of nondimensionalized DEs $$ \begin{array}{lcl} \frac{du_1}{d\tau} & = & u_1(1 - u_1 - a_{12}u_2)\\ \frac{du_2}{d\tau} & = & \rho u_2(a - a_{21}u_1) \end{array} $$ So $(0,0)$ and $(1,0)$. Are there any more? If so, how did you find them?

I need to demonstrate that there are 3 possible nonzero steady states if r and q lie in a domain in r,q space given approximately by rq>4. Could this model exhibit hysteresis? The below ODE is nondimensionalized. $0<\varepsilon\ll 1$ $\displaystyle \frac{du}{d\tau} = ru\left(1 -...

A tilted top that would otherwise topple over can somehow not do so if it spins on an axis fast enough, but only if that axis also pivots fast enough circumferentially with respect to a "principal axis". Often conservation of angular momentum is used to predict this. But the rotational pull away...

Hello all, first time poster here so please go easy :) I have to create a set of Power curves (Power Required and Power Available vs. Velocity) for a propeller-driven Ryan Navion A aircraft at intervals of 1000m. My question to you is this, due to the fact that the aircraft is in steady...

Hello to everyone. I am new with this forum and I am asking help with PDE. I have a linear PDE: L f(x,y,t) = 0 where L is a second order linear operator depending on x, y, their partial derivatives, and t, but not on derivatives with respect to t. The question...

Homework Statement Hey. I am taking a MATLAB class and my instructor is absolutely horrendous. he does not teach us anything, but asks questions on everything. I'm having a problem with the following question: http://imageshack.us/photo/my-images/641/55811089.png/ What is a...